1

Heidelberg Retina Tomograph und PapilleMedline Abstracts November 1996 bis August 2001

Invest Ophthalmol Vis Sci 2001 Aug;42(9):1993-2003Detecting early glaucoma by assessment of retinal nerve fiber layer thickness and visualfunction.Bowd C, Zangwill LM, Berry CC, Blumenthal EZ, Vasile C, Sanchez-Galeana C, Bosworth CF,Sample PA, Weinreb RN.Glaucoma Center, Department of Ophthalmology, University of California San Diego, La Jolla92093-0946, USA.

PURPOSE: To compare the abilities of scanning laser polarimetry (SLP), optical coherencetomography (OCT), short-wavelength automated perimetry (SWAP), and frequency-doublingtechnology (FDT) perimetry to discriminate between healthy eyes and those with early glaucoma,classified based on standard automated perimetry (SAP) and optic disc appearance. To determinethe agreement among instruments for classifying eyes as glaucomatous. METHODS: One eye ofeach of 94 subjects was included. Healthy eyes (n = 38) had both normal-appearing optic discs andnormal SAP results. Glaucoma by SAP (n = 42) required a repeatable abnormal result (glaucomahemifield test [GHT] or corrected pattern standard deviation [CPSD] outside normal limits).Glaucoma by disc appearance (n = 51) was based on masked stereoscopic photograph evaluation.Receiver operating characteristic (ROC) curve areas, sensitivities, and specificities were calculatedfor each instrument separately for each diagnosis. RESULTS: The largest area under the ROC curvewas found for OCT inferior quadrant thickness (0.91 for diagnosis based on SAP, 0.89 for diagnosisbased on disc appearance), followed by the FDT number of total deviation plot points of < or =5%(0.88 and 0.87, respectively), SLP linear discriminant function (0.79 and 0.81, respectively), andSWAP PSD (0.78 and 0.76, respectively). For diagnosis based on SAP, the ROC curve area wassignificantly larger for OCT than for SLP and SWAP. For diagnosis based on disc appearance, theROC curve area was significantly larger for OCT than for SWAP. For both diagnostic criteria, atspecificities of > or =90% and > or =70%, the most sensitive OCT parameter was more sensitivethan the most sensitive SWAP and SLP parameters. For diagnosis based on SAP, the most sensitiveFDT parameter was more sensitive than the most sensitive SLP parameter at specificities of > or=90% and > or =70% and was more sensitive than the most sensitive SWAP parameter atspecificity of > or =70%. For diagnosis based on disc appearance at specificity of > or =90%, themost sensitive FDT parameter was more sensitive than the most sensitive SWAP and SLPparameters. At specificity > or = 90%, agreement among instruments for classifying eyes asglaucomatous was poor. CONCLUSIONS: In general, areas under the ROC curve were largest(although not always significantly so) for OCT parameters, followed by FDT, SLP, and SWAP,regardless of the definition of glaucoma used. The most sensitive OCT and FDT parameters tendedto be more sensitive than the most sensitive SWAP and SLP parameters at the specificitiesinvestigated, regardless of diagnostic criteria.

Arch Ophthalmol. 2001 Jul;119(7):1069-70Discriminating between normal and glaucomatous eyes using the Heidelberg RetinaTomograph, GDx Nerve Fiber Analyzer, and Optical Coherence Tomograph.Zangwill LM, Bowd C, Berry CC, Williams J, Blumenthal EZ, Sanchez-Galeana CA, Vasile C,Weinreb RN.Glaucoma Center, Department of Ophthalmology, University of California-San Diego, La Jolla, CA92093-0946, USA.

2

OBJECTIVE: To compare the ability of 3 instruments, the Heidelberg Retina Tomograph (HRT),the GDx Nerve Fiber Analyzer (GDx), and the Optical Coherence Tomograph (OCT), todiscriminate between healthy eyes and eyes with early to moderate glaucomatous visual field loss.SUBJECTS AND METHODS: Forty-one patients with early to moderate glaucomatous visual fieldloss and 50 healthy subjects were included in the study. The HRT, GDx, and OCT imaging andvisual field testing were completed on 1 eye from each subject within a 6-month interval. Statisticaldifferences in sensitivity at fixed specificities of 85%, 90%, and 95% were evaluated. In addition,areas under the receiver operating characteristic (ROC) curve were compared. RESULTS: Nosignificant differences were found between the area under the ROC curve and the best parameterfrom each instrument: OCT thickness at the 5-o'clock inferior temporal position (mean +/- SE, 0.87+/- 0.04), HRT mean height contour in the nasal inferior region (mean +/- SE, 0.86 +/- 0.04), andGDx linear discriminant function (mean +/- SE, 0.84 +/- 0.04). Twelve HRT, 2 GDx, and 9 OCTparameters had an area under the ROC curve of at least 0.81. At a fixed specificity of 90%,significant differences were found between the sensitivity of OCT thickness at the 5-o'clock inferiortemporal position (71%) and parameters with sensitivities less than 52%. Qualitative assessment ofstereophotographs resulted in a sensitivity of 80%. CONCLUSION: Although the area under theROC curves was similar among the best parameters from each instrument, qualitative assessment ofstereophotographs and measurements from the OCT and HRT generally had higher sensitivitiesthan measurements from the GDx.

Am J Ophthalmol 2001 Jul;132(1):57-62Interobserver variability of optic disk variables measured by confocal scanning lasertomography.Iester M, Mikelberg FS, Courtright P, Burk RO, Caprioli J, Jonas JB, Weinreb RN, Zangwill L.Department of Ophthalmology, University of British Columbia, Vancouver, Canada.

PURPOSE: To assess the interobserver variation of confocal laser scanning tomographicmeasurements of the optic nerve head and to address the question of whether the addition of clinicaloptic disk photographs is helpful in outlining the optic disk margin and in reducing the observer-related variation of the measurements. PATIENTS AND METHODS: Optic disk variables for 16eyes of 16 patients with glaucoma, generated by confocal laser scanning laser tomography(Heidelberg Retina Tomograph), were independently evaluated by four experienced glaucomaspecialists, and the interobserver variability was calculated. A second separate review by the sameobservers included the use of clinical stereoscopic color optic nerve head photographs to aiddefinition of the optic disk margin. RESULTS: Optic disk parameters with the smallestinterobserver variation were cup shape measure, maximum cup depth, height variation contour, andmean height contour. The intraobserver variation of these parameters did not increase when clinicaloptic disk slides were additionally available. Parameters with the highest interobserver variationwere volume below surface, volume below reference, volume above surface, and volume abovereference. The observer variation of these optic disk parameters increased significantly for two ofthe four examiners when clinical optic disk slides were additionally available for outlining the opticdisk margin. CONCLUSION: Confocal laser scanning tomography of the optic nerve head can beimproved significantly if clinical optic disk photographs are additionally available to help inoutlining the optic disk margin. Because interobserver variation in the tomographic optic diskmeasurements can be significant, even if experienced observer are involved, tomographic optic diskmeasurements may be centralized in reading centers in the case of multicenter studies.

Am J Ophthalmol 2001 Jun;131(6):716-721The effects of astigmatism and working distance on optic nerve head images using aHeidelberg Retina Tomograph scanning laser ophthalmoscope.

3

Sheen NJ, Aldridge C, Drasdo N, North RV, Morgan JE.Department of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom.

PURPOSE: To determine effects of astigmatism and working distance on optic nerve head imagesin normal patients using the Heidelberg Retina Tomograph. METHODS: The optic disks of 51normal healthy subjects, aged 19 to 44 years, were imaged through dilated pupils. Subjects with0.75 DC or less of astigmatism were imaged without correction at a working distance of 15 mm.They were then re-imaged with a cylindrical correction of +3.00 DC at 90 degrees axis (n = 20).Naturally astigmatic subjects with more than 1.00 DC were imaged without correction and then re-imaged once this was neutralized with their appropriate spectacle prescription (n = 15). The effectsof working distance were studied using subjects with 0.75 DC or less (n = 16). Two workingdistances were used, 15 and 25 mm. At each session the means of three topographic images weretaken from which standard deviations and parameters were recorded. Parameters analyzed includedcup shape measure, rim area, and inferior temporal rim volume. Z-profile full width at halfmaximum was calculated from one image per subject for each condition. RESULTS: No significantdifference was found in the measured parameters of the optic disk for any astigmatic condition orchanges in working distance (P >.05), (paired t test). Both the standard deviation of the meantopographic images and the Z-profile half-maximum width of the axial intensity profile weresignificantly greater with induced astigmatism of +3.00 DC (P values 0.3 and.00, respectively).CONCLUSIONS: Optic disk parameters are not significantly affected by uncorrected astigmatism(up to 2.50 DC) or working distance. The algorithm used by the Heidelberg Retina Tomograph togenerate topographic maps is sufficiently robust that astigmatism up to 2.50 DC does not requirecorrection.

Optom Vis Sci 2001 Jun;78(6):431-435Age-related topographical changes in the normal human optic nerve head measured byscanning laser tomography.Kergoat H, Kergoat MJ, Justino L, Lovasik JV.School of Optometry, University of Montreal, Quebec, Canada. helene.kergoat@umontreal.ca

PURPOSE: This study was designed to investigate the effects of advanced aging on the optic nervehead (ONH) structure and retinal nerve fiber layer (RNFL) thickness in the eldest segment of ourpopulation. METHODS: Twenty-seven healthy elderly subjects between 75 and 88 years of age(average, 80.1 +/- 0.83 years) and 30 healthy younger subjects between 20 and 32 years of age(average, 23.1 +/- 0.50 years) were recruited for a cross-sectional comparison between ONHmorphology and RNFL thickness as measured by scanning laser tomography. The ONH disc, cup,and rim areas; cup-to-disc ratio; and the mean thickness of the RNFL were quantified. RESULTS:The cup and disc areas as well as the cup-to-disc area ratio increased with age, whereas the RNFLthickness decreased during the course of normal senescence. CONCLUSIONS: Any diagnoses ofocular pathology in the elderly must differentiate the effects of normal aging on the ONHtopography and RNFL thickness. To that effect, the present study provides a clinical profile ofocular structures that extend into the oldest geriatric age group.

Ophthalmic Physiol Opt 2001 May;21(3):173-181The influence of contour line size and location on the reproducibility of topographicmeasurement with the Heidelberg Retina Tomograph.Roff EJ, Hosking SL, Barnes DA.Neurosciences Research Institute, School of Life and Health Sciences, Aston University, AstonTriangle, Birmingham B4 7ET, UK.

4

BACKGROUND: The recommended contour line (CL) location with the Heidelberg RetinaTomograph (HRT) is on the inner edge of Elschnig's scleral ring. This study investigated HRTparameter reproducibility when: (i) the CL size is altered relative to Elschnig's ring; (ii) the CL iseither redrawn or imported between images. METHODS: Using the HRT, seven 10 degrees imageswere acquired for 10 normal volunteers and 10 primary open angle glaucoma (POAG) subjects. ACL was drawn on one image for each subject using Elschnig's scleral ring for reference andimported into subsequent images. The CL diameter was then (a) increased by 50 microns; (b)increased by 100 microns; and (c) decreased by 50 microns. To investigate the effect of the methodof contour line transfer between images a CL was: (1) defined for one image and imported to 6subsequent images; (2) drawn separately for each image. RESULTS: Parameter variabilityimproved as the size of the CL increased for the normal group relative to Elschnig's ring but wasunchanged in the POAG group. The export/import function (method 1) resulted in better parameterreproducibility than the redrawing method for both groups. CONCLUSIONS: The exporting andimporting function resulted in better parameter variability for both subject groups and should beused for transferring CLs across images for the same subject. Increasing the overall CL size relativeto Elschnig's scleral ring improved the reproducibility of the measured parameters in the normalgroup. No significant difference in parameter variability was observed for the POAG group. Thissuggests that the reproducibility of HRT images are affected more by the variation in topographybetween images than change in CL definition.

Surv Ophthalmol 2001 May;45�e�:S297-S303Clinical detection of optic nerve damage: measuring changes in cup steepness with use of anew image alignment algorithm.Burk RO, Rendon R.Department of Ophthalmology, University of Heidelberg, Heidelberg, Germany.burk,reinhard@sk-bielefeld.de

The purpose of this study was to study the effect of a subpixel image alignment algorithm on thestandard deviation (SD) of mean topography images obtained by laser scanning tomography and toevaluate changes of the cup shape measure parameter (CSM) over time based upon the individualparameter variability using the new algorithm. Triple measurements from optic nerve heads of 132eyes of 132 subjects were obtained using the Heidelberg Retina Tomograph HRT. To calculate amean topography image from three single topography images, alignment of the raw optical sectionimage data was performed with the standard software and again with a new subpixel-based imagealignment algorithm. The effect on the averaged (SD) of the mean topography images wasevaluated. CSM was evaluated in 15 eyes of 15 normal subjects (N) and 28 eyes of 14 glaucomapatients (G) over a period of 28.6 +/- 4.6 months (N) and 28.56 +/- 5.2 months (G) respectively. Achange in the CSM value over time was considered significant if CSM measurements exceeded twostandard deviations of this variable determined for the individual eye. Mean-topography image SDwas 22.86 +/- 8.2 microns (min. 9.5 microm; max. 47.8 microm) with the standard alignmentprocedure and 15.46 +/- 6.8 microm (min. 6.8 microm; max. 42.8 microm) with the new algorithm.The average SD improvement was 7.46 +/- 3.9 microns (min. -8.1 microm; max. 28.7 microm). Thecoefficient of correlation of both methods was R(2) = 0.77 (p < 0.0001). No control group eyedemonstrated significant changes of CSM in the follow-up period. The CSM indicated an increasein cup steepness in 4 eyes of 4 glaucoma patients. In one of these four eyes, a deterioration of thevisual field was identified by white on white perimetry. The new image alignment algorithmsignificantly reduces the SD of mean topography images calculated from identical raw data. Iftopometric variables are evaluated over time, the individual variability of data should be taken intoaccount.

5

Curr Opin Ophthalmol 2001 Apr;12(2):100-104The diagnostic value of optic nerve imaging in early glaucoma.Mardin CY, Junemann AG.Department of Ophthalmology, Friedrich-Alexander Universitat Erlangen-Nurnberg, Erlangen,Germany. christian.mardin@augen.imed.uni-erlangen.de

In the last decade, new imaging techniques have been added to conventional fundus photographyand have been evaluated for use in early glaucoma. They all measure the loss of neuroretinal rim orretinal nerve fiber layer as a correlate to glaucomatous ganglion cell and axon loss. The value ofoptic disc photography, planimetry, laser scanning tomography, laser scanning polarimetry, andoptical coherence tomography for the diagnosis of glaucomatous eyes in a preperimetric or earlyperimetric stage is analyzed on the basis of sensitivity, specificity, and receiver operatingcharacteristics (ROC) curves. It becomes clear that all these techniques allow a more or less semi-automated evaluation of the optic disc and retinal nerve fiber layer but still have their limitations inthe diagnosis of a very early, preperimetric stage of the glaucoma disease.

J Glaucoma 2001 Apr;10(2):95-101Ability of peripapillary atrophy parameters to differentiate normal-tension glaucoma fromglaucomalike disk.Park KH, Park SJ, Lee YJ, Kim JY, Caprioli J.Department of Ophthalmology, Seoul National University College of Medicine, Korea.

PURPOSE: To investigate the ability of peripapillary atrophy (PPA) parameters to differentiatenormal-tension glaucoma (NTG) from glaucomalike disk (GLD). METHODS: Thirty-three eyes of33 patients with GLD that had no evidence of visual field defect and retinal nerve fiber layer defectand 33 eyes of 33 patients with NTG, matched with age and intraocular pressure, were enrolled.The participants were selected from the database of patients referred from a routine health checkupbecause of high cup-to-disk ratio (>0.5). Topographic measurements for the optic disk wereperformed using the Heidelberg Retina Tomograph (HRT). The extent of PPA (zone beta) wasmeasured with Atrophy Zone Analysis software of HRT. Receiver operating characteristic (ROC)curves (GraphROC version 2.0) were used to compare the new formula including PPA parameterswith that of the HRT discriminant analysis formula in differentiating NTG from GLD. RESULTS:The area of zone beta, atrophy-to-disk area ratio, and angular and radial extent of zone beta weresignificantly larger in NTG (P < 0.01). Multiple logistic regression analysis showed that rim areaand corrected radial extent of zone beta are variables that show significant difference between NTGand GLD (P < 0.05). The area under the ROC curve for the new formula including rim area andcorrected radial extent of zone beta (0.8655) was significantly larger than that for the HRTdiscriminant analysis formula (0.7351) (P = 0.0128). CONCLUSION: The PPA measurementobtained by HRT can be a useful additional tool to differentiate NTG from GLD after the firstscreening by disk photograph in a routine health checkup.

Ophthalmic Physiol Opt 2001 Mar;21(2):139-150How large is the optic disc? Systematic errors in fundus cameras and topographers.Meyer T, Howland HC.Department of Neurobiology and Behavior, W-201 Mudd Hall, Cornell University, Ithaca, NY14853, USA.

PURPOSE: To determine whether or not there are systematic differences in the areas of optic discsas measured by different machines using different measurement algorithms and whether racial orgender differences exist in optic disc area measurements. METHODS: We examined the results of

6

twenty-three published studies on the size of normal optic discs of various patient populations.Studies differed in the type of instrument and method used to measure optic disc area, and thenumber, age, race and gender of subjects examined. Noticing that different machines exhibitedstatistically significant systematic differences in optic disc sizes of comparable populations, wecomputed a "normalization" factor for each machine based on these mean differences. Applying thisnormalization factor to the results, we then re-examined the differences between racial and gendergroups. RESULTS: By comparing the results of mean optic disc areas of different racial groupsmade with different machines, and normalizing results according to those of the Zeiss funduscamera, we found the normalization factors for the following machines to be, Zeiss fundus camera:1 (by definition), Rodenstock Optic Disc Analyzer (RODA): 1.51, Topcon fundus camera: 1.04,Heidelberg Retina Tomograph (HRT): 1.15 and TopSS scanning laser ophthalmoscope: 1.29. Thatis, to bring the results of area measurements made with a RODA machine in line with those madewith a Zeiss fundus camera, one should multiply the former by the factor 1.51. Using thenormalized results, we confirmed the findings of previous authors that the optic disc areas of blacksubjects were statistically significantly larger than those of white subjects (n-weighted mean effect= 0.556 +/- 0.142 S.E., n = 5). Further, the meta-analysis of various racial populations from fivestudies shows that males have significantly larger discs than females (n-weighted mean effect =0.151 +/- .055 S.E., n = 9). CONCLUSION: Different machines and techniques give differentresults when populations of similar racial composition are measured. We recommend applying theabove normalizing factors when comparing studies that employ different instruments.

Br J Ophthalmol 2001 Mar;85(3):297-303Scanning laser ophthalmoscopy of the optic nerve head in exfoliation glaucoma and ocularhypertension with exfoliation syndrome.Harju M, Vesti E.Helsinki University Eye Hospital, PO Box 220, FIN-00029 HYKS, Finland. mika.harju@hueh.fi

AIMS: To study the relation between optic nerve head topography (Heidelberg retina tomograph,HRT) and disc area, visual field index mean defect (MD), and intraocular pressure (IOP), and to seewhether change in HRT parameters is associated with change in MD in a prospective follow up.METHODS: 80 consecutive patients (69 patients with exfoliation glaucoma and 11 with ocularhypertension combined with exfoliation syndrome) were examined before IOP reducingintervention and prospectively followed every 6 months for 2 years. RESULTS: At the entry point,multiple regression analysis showed significant linear association between MD and all HRTparameters, when controlling for disc area. Disc area showed significant association with cup area,cup/disc area ratio, rim area, cup volume, and mean RNFL thickness. Six months after interventionIOP had decreased significantly. Reversible changes in cup area, cup/disc area ratio, rim area, cupvolume, rim volume, mean cup depth, and maximum cup depth were associated with decrease inIOP. During the follow up period from 6 month to 2 years, IOP did not change significantly, andMD was used as a measure of progression of glaucoma. During this period, only cup shape measureamong HRT parameters showed significant association with subsequent change in MD.CONCLUSION: Disc area should be taken into account when using HRT to compare patients. Anyeffect of change in IOP should be also taken into account when using HRT in follow up. Cup shapemeasure is a promising indicator of progression of glaucomatous damage.

Br J Ophthalmol 2001 Mar;85(3):297-303Scanning laser ophthalmoscopy of the optic nerve head in exfoliation glaucoma and ocularhypertension with exfoliation syndrome.Harju M, Vesti E.Helsinki University Eye Hospital, PO Box 220, FIN-00029 HYKS, Finland. mika.harju@hueh.fi

7

AIMS: To study the relation between optic nerve head topography (Heidelberg retina tomograph,HRT) and disc area, visual field index mean defect (MD), and intraocular pressure (IOP), and to seewhether change in HRT parameters is associated with change in MD in a prospective follow up.METHODS: 80 consecutive patients (69 patients with exfoliation glaucoma and 11 with ocularhypertension combined with exfoliation syndrome) were examined before IOP reducingintervention and prospectively followed every 6 months for 2 years. RESULTS: At the entry point,multiple regression analysis showed significant linear association between MD and all HRTparameters, when controlling for disc area. Disc area showed significant association with cup area,cup/disc area ratio, rim area, cup volume, and mean RNFL thickness. Six months after interventionIOP had decreased significantly. Reversible changes in cup area, cup/disc area ratio, rim area, cupvolume, rim volume, mean cup depth, and maximum cup depth were associated with decrease inIOP. During the follow up period from 6 month to 2 years, IOP did not change significantly, andMD was used as a measure of progression of glaucoma. During this period, only cup shape measureamong HRT parameters showed significant association with subsequent change in MD.CONCLUSION: Disc area should be taken into account when using HRT to compare patients. Anyeffect of change in IOP should be also taken into account when using HRT in follow up. Cup shapemeasure is a promising indicator of progression of glaucomatous damage.

Am J Ophthalmol 2001 Feb;131(2):216-222Retinal nerve fiber layer evaluation in human immunodeficiency virus-positive patients.Plummer DJ, Bartsch DU, Azen SP, Max S, Sadun AA, Freeman WR.Shiley Eye Center, Department of Ophthalmology, School of Medicine, University of California-San Diego, La Jolla, CA 92093-0946, USA. dplummer@ucsd.edu

PURPOSE: To determine the effect of human immunodeficiency virus (HIV) infection ontopographic measures of the optic disk and the retinal nerve fiber layer. METHODS: A cross-sectional study at the Acquired Immunodeficiency Syndrome (AIDS) Ocular Research Unit at theUniversity of California, San Diego. Retinal nerve fiber layer thickness at the optic nerve head wasevaluated using the Heidelberg Retinal Tomograph, a confocal scanning laser tomograph in 38HIV-positive and 24 age-matched HIV-negative subjects. RESULTS: HIV-positive patients withoutCMV retinitis showed significant differences from HIV-negative normal controls in a number ofmeasures of the retinal nerve fiber layer. This indicated a loss of retinal ganglion cells in HIV-positive patients without retinitis. HIV-positive patients with CMV retinitis were worse in mostmeasurements than both HIV-negative controls and HIV-positive patients without CMV.CONCLUSIONS: Significant thinning of the retinal nerve fiber layer occurs in HIV-positivepatients without infectious retinopathy, and there are further changes in the optic disk associatedwith CMV retinitis. Confocal scanning laser tomography may be of use in the diagnosis of earlyHIV-associated visual function loss.

Ophthalmology 2000 Dec;107(12):2272-2277Identifying early glaucomatous changes. Comparison between expert clinical assessment ofoptic disc photographs and confocal scanning ophthalmoscopy.Wollstein G, Garway-Heath DF, Fontana L, Hitchings RA.Glaucoma Unit, Moorfields Eye Hospital, London, UK. Department of Ophthalmology, ShaareZedek Medical Center, Jerusalem, Israel.

OBJECTIVE: To compare the ability of expert clinicians, using qualitative assessment ofstereoscopic optic disc photographs, and confocal scanning laser ophthalmoscope imaging todiscriminate between healthy persons and patients with early glaucoma. DESIGN: Comparative

8

instrument validation study. PARTICIPANTS: Seventy-two healthy persons and 51 patients withearly glaucoma (average visual field mean deviation, -3.6 dB). Early glaucoma was defined as ahistory of ocular hypertension and a reproducible visual field defect scoring 5 or less in theAdvanced Glaucoma Intervention Study classification, regardless of optic disc appearance.INTERVENTION: Stereoscopic optic nerve head (ONH) photography and Heidelberg RetinaTomograph (HRT) imaging, (Heidelberg Engineering GmbH, Dossenheim, Germany). MAINOUTCOME MEASURES: Ability of clinical assessment of stereoscopic ONH photographs andanalysis of HRT parameters, taking into account the optic disc size, to detect early glaucomatousoptic disc changes. RESULTS: The specificity of the majority opinion of five observers to detectearly glaucomatous optic disc changes was 94.4%, with a sensitivity of 70.6%. Using the HRTanalysis, the specificity was 95.8% and the sensitivity was 84. 3%. CONCLUSIONS: HeidelbergRetina Tomograph image analysis that takes into account the optic disc size is more sensitive thanclinical assessment of stereoscopic optic disc photographs in distinguishing between healthypersons and patients with early glaucoma.

Ophthalmology 2000 Dec;107(12):2267-2271Glaucomatous optic disc changes in the contralateral eye of unilateral normal pressureglaucoma patients.Wollstein G, Garway-Heath DF, Poinoosawmy D, Hitchings RA.Glaucoma Unit, Moorfields Eye Hospital, City Road, London, UK.

OBJECTIVE: To evaluate the optic disc for structural abnormalities in the contralateral eye ofunilateral normal pressure glaucoma patients. DESIGN: Cross-sectional study. PARTICIPANTS:Fifty-three unilateral normal pressure glaucoma patients. TESTING: Optic disc imaging with theHeidelberg Retina Tomograph (HRT). MAIN OUTCOME MEASURES: Optic disc structuralparameters. RESULTS: Of the contralateral (normal visual field) eyes, 79.2% were found to havean abnormal optic disc by HRT analysis. Of the glaucomatous (abnormal visual field) eyes, 94.3%were found to have an abnormal disc. The patterns of disc abnormality were defined as marked ormoderate diffuse thinning of the neuroretinal rim (NRR) or broad or narrow focal thinning of theNRR. The most common pattern in the contralateral eyes was moderate diffuse thinning of the NRR(45.2%). The most frequently abnormal segments were the nasal superior (73. 8%) followed by thenasal inferior and the global NRR parameter (both 54.8%). CONCLUSIONS: A high frequency ofNRR thinning was found in the contralateral (normal visual field) eyes of unilateral normal pressureglaucoma patients by HRT analysis. Knowing whether these abnormalities predict futureprogression to the development of visual field abnormality must wait until longitudinal studies arecompleted. If a disc abnormality is shown to predict future field loss, then early identification willallow early treatment.

Graefes Arch Clin Exp Ophthalmol 2000 Sep;238(9):746-751Three-dimensional analysis of measurements of the Heidelberg Retina Tomograph.Muller-Richter UD, Malig HJ, Schwerdtner A, Lang M, Hille K, Ruprecht KW.Augenklinik und Poliklinik der Universitat des Saarlandes, Homburg, Germany.

BACKGROUND: With the aid of scanning laser tomography, feasible with the Heidelberg RetinaTomograph (HRT), refined structures can be measured three-dimensionally. Pictures are built upfrom scanned layers which are represented as two-dimensional topographical or reflectivity picturesby the HRT software. The kind of information that is provided by the third dimension can beexploited much better by real spatial three-dimensional presentation. The autostereoscopic Dresden3D display makes such a spatial presentation feasible as add-on to the HRT. METHODS: Seventeenpatients (9 women, 8 men) were chosen on the basis of a long duration of observation (mean 42.41

9

months) and a large number of follow-up examinations (mean 5.29). These patients were examinedwith the HRT as well as with the Dresden 3D display. The results were compared regarding theircorrelation pairs. RESULTS: Comparing the correlation pairs (r>0.7) the Dresden 3D displayprovided a higher Pearson correlation coefficient with 8 out of 10 pairs. It was evident that theevaluations of the two devices referred to the same parallel structures. DISCUSSION: The Dresden3D display facilitates, with its form of presentation, a better evaluation of the measurements of theHRT. More precise evaluation of retinal structures by virtue of the autostereoscopic display presentsan improvement.

Br J Ophthalmol 2000 Sep;84(9):993-998Use of sequential Heidelberg retina tomograph images to identify changes at the optic disc inocular hypertensive patients at risk of developing glaucoma.Kamal DS, Garway-Heath DF, Hitchings RA, Fitzke FW.Glaucoma Unit, Moorfields Eye Hospital, London EC1V 2PD.

AIM: To determine if global and segmental changes in optic disc parameters of sequentialHeidelberg retina tomograph (HRT) images develop in individual ocular hypertensive (OHT)patients without white on white visual field defects. METHODS: Patients and normal controls wererecruited from a prospective ocular hypertension treatment trial. The subject groups consisted of 21OHT patients who had converted to early glaucoma on the basis of visual field criteria (24-2program on the Humphrey perimeter), 164 OHT subjects with normal visual fields, and 21 normalcontrols. Sequential HRT images 16-21 months apart were obtained for each subject and segmentaloptic disc parameters were measured to determine if any change had occurred. From the analysis ofsequential HRT images of the 21 normal eyes we established normal limits of interimage variation.Individual discs in each group showing changes above the 95% limit of normal variability werethen sought. RESULTS: Several segmental and global optic disc parameters were found to showsignificant change in the converter group before confirmed visual field change, confirming ourpreviously published results. Individual optic disc analysis using the 95% limit of normal variabilitydata demonstrated glaucomatous change in 13 out of 21 converter eyes. 47 of the 164 OHT eyeswith normal visual fields showed change in global and segmental parameters in a "glaucomatous"direction above the level expected for normal variability. The parameters which changed mostfrequently in the OHT eyes were: global cup volume (6.7% of discs), inferonasal cup volume(11%), inferotemporal cup volume (8.5%), and superotemporal cup area (7.3%). CONCLUSIONS:We have identified change in a subset of ocular hypertensive patients which could predate thedevelopment of glaucomatous visual field loss. The HRT could be of value in the sequential followup of those suspected of having glaucoma by identifying eyes at risk of developing glaucoma.However, further refinement of the technique is required to eliminate some of the inherentvariability of the analysis method described, and to increase the ability to detect at risk individuals.

Am J Ophthalmol 2000 Sep;130(3):280-286Optic disk topography after medical treatment to reduce intraocular pressure.Bowd C, Weinreb RN, Lee B, Emdadi A, Zangwill LM.Glaucoma Center and Diagnostic Imaging Laboratory, Department of Ophthalmology, Universityof California, San Diego, La Jolla,

PURPOSE: We examined changes in optic disk topography using confocal scanning laserophthalmoscopy after reducing intraocular pressure with administration of latanoprost. METHODS:Twenty-nine patients with glaucoma or ocular hypertension were imaged using the HeidelbergRetina Tomograph before and after the administration of latanoprost to decrease intraocularpressure. Average time between pretreatment and posttreatment imaging was 2.7 +/- 1.8 weeks.

10

Heidelberg Retina Tomograph software-measured parameters were mean height of contour, cuparea, cup volume, mean cup depth, maximum cup depth, cup shape, rim area, rim volume, cup-to-disk ratio, and retinal nerve fiber thickness. RESULTS: Average intraocular pressure decreasedsignificantly (mean +/- SD) by 7.2 +/- 5.4 mm Hg (25 +/- 16% decrease). No statistically significantchanges in measured topographic parameters were found. When data from patients with decreasesin intraocular pressure of 7 mm Hg or greater were analyzed separately (mean intraocular pressuredecrease = 10.79 +/- 4.32 mm Hg, 36 +/- 8% decrease), cup area (P =.005), cup volume (P =. 002),and cup-to-disk ratio (P =.005) decreased significantly, and rim area (P =.005) increasedsignificantly. Linear regression analysis of the data from all subjects showed that a change inintraocular pressure after latanoprost administration accounted for 12% or more of the variance intwo measured topographic parameters (mean cup depth and cup shape). CONCLUSIONS: Theseresults suggest that, in some patients, moderate decreases in intraocular pressure may affect disktopography, as measured by Heidelberg Retina Tomograph. Intraocular pressure should beconsidered when analyzing consecutive confocal scanning laser ophthalmoscopy images forglaucomatous progression.

Klin Monatsbl Augenheilkd 2000 Aug;217(2):82-87Monitoring of morphometric changes of optic discs with morphologic progression ofglaucomatous optic atrophy by means of laser scanner tomography.Mardin CY, Horn F, Budde WM, Jonas JB.Augenklinik mit Poliklinik der Universitat Erlangen-Nurnberg. christian.mardin@augen.imed.uni-erlangen.de

AIM: Aim of this study was to measure morphometric changes in optic discs with laser-scanningtomography (HRT, Heidelberg-Retina-Tomograph, Heidelberg) in eyes with early glaucomatousmorphologic progression. PATIENTS AND METHODS: 61 eyes of 36 patients with markedneuroretinal rim loss or its early morphologic signs (1. optic disc hemorrhages, 2. reduced visibilityof the retinal nerve fiber layer (RNF), 3. appearance of narrowing of retinal vessels, 4. enlargementof the choroidal, parapapillary atrophy) were compared to 74 normal eyes of 39 probands. 15degrees stereographs of the optic discs were evaluated for morphologic changes. The morphometricvariables of the neuroretinal rim and excavation measured by the HRT were examined in the courseof the disease. RESULTS: In the group of normals no significant changes of the neuroretinal rim inthe course of 2.0 +/- 1.2 years were found. In the group of glaucomatous eyes (3.0 +/- 1.5 yearsfollow-up) 34 eyes showed marked neuroretinal rim loss, 17 disc hemorrhages, 4 vessel narrowing,3 an increased chorioidal atrophy, 3 a decreased visibility of the retinal nerve fiber layer. In theseeyes a significant loss of rim area (p = 0.01) and an increase of excavation area (p = 0.0001) andvolume (p = 0.003) was measured by the HRT. Only three eyes showed a perimetric loss ofsensitivity (0.8-3.4 db) in Octopus static perimetry. CONCLUSIONS: Laser-scanning tomographyof the optic disc seems to be able to measure morphometric changes in eyes with morphologicprogression of glaucomatous optic atrophy, even before perimetric changes occur.

Graefes Arch Clin Exp Ophthalmol 2000 Aug;238(8):669-676Measurement of a novel optic disc topographic parameter, "spikiness", in glaucoma.Morgan-Davies J, King AJ, Aspinall P, O'Brien CJ.Visual Impairment Research Group, Heriot Watt University, Edinburgh, Scotland, UK.

BACKGROUND: Structural changes in the lamina cribrosa have been implicated in thepathogenesis of glaucomatous optic atrophy, but not observed. This paper presents a novelparameter of topographic variability within the optic disc, termed "spikiness", which may reflectglaucoma-related changes in the lamina. METHODS: Four age-matched groups of normal patients

11

(n=12, mean age 64.8 years) and patients with ocular hypertension (n=14, mean age 63.1), primaryopen-angle glaucoma (n=11, mean age 70) and low-tension glaucoma (n=15, mean age 66.3) wererecruited. Images of normal and glaucomatous eyes from the Heidelberg Retina Tomograph wereimported into ERDAS image processing software where the spikiness data (30 consecutive meansurface height values across the base of the optic cup in both the vertical and horizontal meridians)were extracted in a format that facilitated further statistical analysis. RESULTS: Significantdifferences in topographic variability (spikiness) existed in the vertical (F=3.64, P=0.01) but not thehorizontal meridian (F=1.25, P=0.3) through the optic disc. Spikiness was inversely related toHumphrey mean deviation (P<0.05), and cup-disc ratio (P<0.004) and was directly related to nervefibre layer thickness (P<0.005). Of particular interest was the finding that the spikiness measurewas the only optic disc parameter to significantly discriminate low tension glaucoma from primaryopen angle glaucoma. CONCLUSION: A new measure of surface variability (topography) at thefloor of the optic cup has been described. The new index of spikiness may represent a measurementof lamina cribrosa fragility which has been implicated, but not previously estimated, inglaucomatous eyes.

Automated analysis of normal and glaucomatous optic nerve head topography images.Swindale_NV; Stjepanovic_G; Chin_A; Mikelberg_FSInvest Ophthalmol Vis Sci, 2000 06, 41: 7, 1730-42

PURPOSE: To classify images of optic nerve head (ONH) topography obtained by scanning laserophthalmoscopy as normal or glaucomatous without prior manual outlining of the optic disc.METHODS: The shape of the ONH was modeled by a smooth two-dimensional surface with ashape described by 10 free parameters. Parameters were adjusted by least-squares fitting to give thebest fit of the model to the image. These parameters, plus others derived from the image using themodel as a basis, were used to discriminate between normal and abnormal images. The method wastested by applying it to ONH topography images, obtained with the Heidelberg Retina Tomograph,from 100 normal volunteers and 100 patients with glaucomatous visual field damage. RESULTS:Many of the parameters derived from the fits differed significantly between normal andglaucomatous ONH images. They included the degree of surface curvature of the disc regionsurrounding the cup, the steepness of the cup walls, the goodness-of-fit of the model to the image inthe cup region, and measures of cup width and cup depth. The statistics of the parameters wereanalyzed and were used to construct a classifier that gave the probability, P(G), that each imagecame from the glaucoma population. Images were classified as abnormal if P(G) > 0.5. Theprobabilities assigned to each image were in most cases close to 0 (normal) or 1 (abnormal). Eighty-seven percent of the sample was confidently classified with P(G) < 0.3 or P(G) > 0.7. Within thisgroup, the overall classification accuracy was 92%. The overall accuracy of the method (the meanof sensitivity and specificity, which were similar) in the whole sample was 89%. CONCLUSIONS:ONH images can be classified objectively and dependably by an automated procedure that does notrequire prior manual outlining of disc boundaries.

Graefes Arch Clin Exp Ophthalmol 2000 Jun;238(6):477-481Search for an optimal combination of structural and functional parameters for the diagnosisof glaucoma. Multivariate analysis of confocal scanning laser tomograph, blue-on-yellowvisual field and retinal nerve fiber layer data.Vihanninjoki K, Teesalu P, Burk RO, Laara E, Tuulonen A, Airaksinen PJ.Department of Ophthalmology, University of Oulu, Finland.

BACKGROUND: The purpose of this study was to evaluate which of the structural and functionalparameters--the Heidelberg Retina Tomograph (HRT), white-on-white (W/W) and blue-on-yellow

12

(B/Y) visual fields and semiquantitative retinal nerve fiber layer (RNFL) scoring parameters--cangive the best separation between non-glaucomatous and glaucomatous eyes. METHODS: Fifty-fivesubjects were included in this study: 32 nonglaucomatous subjects with mean age of 54 years, and23 patients with ocular hypertension or glaucoma and mean age of 59 years. The HRT withsoftware 1.11, the Humphrey 30-2 W/W and lens coloration-corrected B/Y visual fields, andsemiquantitative RNFL scores were utilized. Stepwise logistic regression analysis was used infinding, from a given set of parameters, a best discriminating parsimonious subset to a logisticmodel, the discriminatory performance of which was evaluated by the area under the ROC curve.RESULTS: When all the structural and functional variables were considered, the RNFL totaloverall score gave the best separation between glaucomatous and non-glaucomatous eyes (ROCarea 0.98). Without the RNFL scores and optic disc size-dependent HRT parameters in the model,the cup shape measure was selected first (ROC area 0.88). In the second step the RNFL thicknesswas selected (ROC area 0.91), and in the third step the corrected B/Y mean deviation (MD) wasselected (ROC area 0.91). With only the HRT parameters in the model, the cup/disc ratio wasselected first (ROC area 0.88). However, when the groups were matched for optic disc size, all discsize-dependent HRT variables lost their discriminant power. CONCLUSION: Cup shape measureand RNFL thickness, together with age- and lens coloration-corrected MD of the B/Y perimetryprovided good discrimination between healthy individuals and patients with glaucoma.

Graefes Arch Clin Exp Ophthalmol 2000 May;238(5):375-384Development of the standard reference plane for the Heidelberg retina tomograph.Burk RO, Vihanninjoki K, Bartke T, Tuulonen A, Airaksinen PJ, Volcker HE, Konig JM.Department of Ophthalmology, University of Heidelberg, Germany. reinhard_burk@med.uni-heidelberg.de

BACKGROUND: Topometry of the optic disc is the quantitative assessment of the structure of theoptic nerve head by means of three-dimensional parameters. The parameter values depend ondefinitions of intraocular reference planes. PURPOSE: To describe the development of intraocularreference planes in laser scanning tomography for the Heidelberg Retina Tomograph (HRT) usingimage intrinsic data with a fixed offset reference plane (320 microm) and to present a contour-line-based "flexible" standard reference plane ("SRP") for calculation of intrapapillary stereometricparameters taking the interindividual variability of optic disc topography into account. METHODS:Ten-degree triple images were obtained by laser scanning tomography from 99 glaucoma eyes and180 normal eyes. The images were evaluated to assess the variability of height measurements of anoptic disc border contour-line segment (6 degrees width) corresponding to the site of the papillo-macular bundle as indicated by the average optic disc surface inclination angle. RESULTS: Theaverage optic disc surface inclination angle was -7 degrees +/- 3 degrees below the horizontalmeridian (0 degrees). The 6 degrees wide contour-line segment for the SRP was chosen accordingto the average surface inclination angle (-10 degrees to -4 degrees). The reproducibility of the SRP-segment height measurements was 16.0+/-10.8 microm for normal eyes and 23.4+/-18.0 microm forglaucoma eyes. To ensure that the automatic reference level determination for intrapapillaryparameters remained below the disc border height, we defined the SRP level at a 50 microm offset(>2 SD of average segment height reproducibility in glaucoma) added to the individual heightposition of the 6 degrees contour line segment. CONCLUSION: The flexible standard referenceplane allows for automatic determination of intrapapillary variables once a disc border contour lineis interactively defined. In contrast to a fixed offset reference plane (e.g. 320 microm below themean retina height), the interindividual variability of optic disc topography (oblique insertion,glaucomatous surface flattening) is respected at the cost of the need for an accurate optic discborder outline.

13

Measurement of peripapillary retinal nerve fiber layer volume in glaucoma.King_AJ; Bolton_N; Aspinall_P; OBrien_CJAm J Ophthalmol, 2000 05, 129: 5, 599-607

PURPOSE: To measure peripapillary retinal nerve fiber layer volume in normal subjects andpatients with ocular hypertension, primary open-angle glaucoma, and low-tension glaucoma.METHODS: Sixty-five subjects were classified into four groups of normal subjects and subjectswith ocular hypertension, primary open-angle glaucoma, and low-tension glaucoma on the basis ofintraocular pressure measurements, visual field loss, and optic disk appearance. Groups werematched for sex, age, and optic disk area. Peripapillary retinal nerve fiber layer volumemeasurements were made with a modification of software version 1.11 of the Heidelberg RetinaTomograph confocal scanning laser ophthalmoscope. Retinal nerve fiber layer volumemeasurements were taken at 0.1-mm increments from the disk margin for a global 360-degreeassessment and at four predefined segments using two different reference planes. Statistical analysiswas carried out using analysis of variance with Bonferroni correction. RESULTS: Retinal nervefiber layer volume measurements showed a gradation from normal to ocular hypertension and fromocular hypertension to glaucoma groups. Mean group measurements showed statistically significantdifferences (P <.05) in peripapillary retinal nerve fiber layer volume for most segmental measuresbetween the groups. Measurements with the default reference plane in the 0.0-mm to 0.1-mm and0.1-mm to 0.2-mm increments for the superotemporal segment showed the greatest differencesbetween groups (P <.00005). CONCLUSION: Peripapillary retinal nerve fiber layer volumemeasurements differ between groups of normal subjects and patients with ocular hypertension,primary open-angle glaucoma, and low-tension glaucoma. This measure offers a further method ofassessment of retinal nerve fiber layer in patients with glaucoma and glaucoma suspects.

Am J Ophthalmol 2000 May;129(5):592-598Relationship between structural abnormalities and short-wavelength perimetric defects ineyes at risk of glaucoma.Ugurlu S, Hoffman D, Garway-Heath DF, Caprioli J.Glaucoma Division, Jules Stein Eye Institute, UCLA School of Medicine, Los Angeles, California,USA.

PURPOSE: To determine the relative prevalence of blue-yellow perimetric defects and structuralabnormalities of the optic nerve and nerve fiber layer in eyes at risk of glaucoma. METHODS:Seventy-two eyes (of 72 patients) at risk of glaucoma, with normal white-on-white full thresholdperimetry, were examined prospectively with blue-yellow full-threshold perimetry (Humphrey).Structural evaluations were conducted with qualitative assessment of stereoscopic color optic diskphotographs and monochromatic nerve fiber layer photographs performed independently by threemasked examiners (a glaucoma specialist and two glaucoma fellows), and statistical analysis ofsummary parameters was obtained with scanning confocal laser tomography (abnormal defined asvalues outside 95% confidence limits established in normal control subjects). RESULTS: Kappavalues for interobserver agreement were 0.64, 0.88, and 0.79 for optic disk evaluation and 0.59,0.60, and 0.61 for nerve fiber layer evaluation. Thirteen (18%) of 72 eyes had blue-yellowabnormalities. A total of 30 eyes (42%) were identified as having a structural abnormality; 29(40%) had qualitatively determined optic disk abnormalities, 21 (29%) had qualitatively determinednerve fiber layer defects, and 26 (36%) had statistically significant structural abnormalities. Twelveof 13 eyes with blue-yellow defects had a detectable structural abnormality; all 12 hadabnormalities identified with disk photography, nine with nerve fiber layer photography, and 12 byscanning laser tomography. CONCLUSIONS: Clinically detectable structural abnormalitiesfrequently coexist with blue-yellow perimetric defects in patients with ocular hypertension. A

14

substantial proportion of patients with ocular hypertension with normal blue-yellow perimetry hasearly detectable glaucomatous structural abnormalities.

Comparison of ranked segment analysis (RSA) and cup to disc ratio in computer-assistedoptic disc evaluation.Gundersen_KG; Asman_PActa Ophthalmol Scand, 2000 04, 78: 2, 137-41

PURPOSE: Ranked segment analysis is a new method for evaluation of optic nerve headtopography with the Heidelberg Retina Tomograph. This analysis ranks sector measurementsaround the optic disc and compares these measurements with rank specific significance limits. Weevaluated the diagnostic precision of the ranked segment analysis in a large clinical sample andcompared with vertical cup/disc ratio measurements. Vertical cup/disc ratio measurements were notcorrected for disc size. METHODS: We analysed optic disc images from 153 normal and 75glaucomatous eyes using the Heidelberg Retina Tomograph (software version 2.01). Rankedsegment analyses and vertical cup/disc ratio measurements were obtained from each optic discimage, and ROC curves were plotted. RESULTS: At the 95% specificity level, sensitivity wassignificantly lower for ranked segment analysis (70%) compared to vertical cup/disc ratiomeasurements (85%). Almost 30% of the discs in the glaucoma group were classified as normalusing the ranked segment analysis. DISCUSSION: Ranked segment analysis yielded unacceptablypoor discrimination, in fact, worse than cup/disc ratio with its known clinical limitationsGlaucomatous disc damage typically occurs at the vertical poles of the disc. High rankmeasurements (low sector values) in normal eyes, on the other hand, are more common in thetemporal disc sectors. Important spatial information is lost during the ranking procedure. This maypartly explain the low sensitivity of the ranked segment analysis observed in our study. The resultsraise serious concerns regarding the clinical usefulness of ranked segment analysis.

Curr Eye Res 2000 Apr;20(4):276-282Interocular differences in optic disc topographic parameters in normal subjects.Gherghel D, Orgul S, Prunte C, Gugleta K, Lubeck P, Gekkieva M, Flammer J.University Eye Clinic Basel, Basel, Switzerland.

PURPOSE: To test the interocular differences in optic disc topography in normal subjects by meansof confocal scanning laser ophthalmoscopy. METHODS: Topographic measurements of the opticdisc were evaluated by means of confocal scanning laser ophthalmoscopy (Heidelberg RetinaTomograph) in 314 eyes of 157 healthy volunteers. The examination was started randomly eitherwith the right eye or the left eye. Differences between right and left eyes in disc area, cup area, cupvolume, cup/disc area ratio, rim area, rim volume, maximum cup depth, cup shape measure, retinalnerve fiber layer thickness, and retinal nerve fiber cross section area for 360 degrees and for thetemporal and nasal regions of the optic nerve head were evaluated by means of Student t-test. Thesame parameters were assessed in a subgroup of 80 elderly (age> 50 years) healthy subjects. Holm'ssequentially rejective method was used for significance correction of multiple comparisons.RESULTS: Significant interocular differences in the average retinal nerve fiber layer thickness (p =0.0010) and retinal nerve fiber layer cross section area (p = 0.0036) were found, with the right eyeshowing, on the average, lower values.The left eye showed a larger retinal nerve fiber layerthickness in 94 subjects (59.87%) and a larger retinal nerve fiber cross section area in 101 subjects(64. 33%). In the temporal optic disc area there were no statistically significant differences intopometric data (p> 0.05). In the nasal area, significant interocular differences in the retinal nervefiber layer thickness (p = 0.0002) and retinal nerve fiber layer cross section area (p = 0.0003) werefound. Similar results were found when the group of subjects older than 50 years was considered.

15

CONCLUSIONS: This study demonstrates systematic interocular differences in optic disctopometric data. Such a finding, be it due to methodological or biological reasons, should be takenin consideration in clinical trials.

Technique for detecting serial topographic changes in the optic disc and peripapillary retinausing scanning laser tomography.Chauhan_BC; Blanchard_JW; Hamilton_DC; LeBlanc_RPInvest Ophthalmol Vis Sci, 2000 03, 41: 3, 775-82

PURPOSE: To describe and evaluate a new statistical technique for detecting topographic changesin the optic disc and peripapillary retina measured with confocal scanning laser tomography.METHODS: The 256x256-pixel array of topographic height values obtained with each image fromthe Heidelberg Retina Tomograph (Heidelberg Engineering, Heidelberg, Germany) was dividedinto an array of 64x64 superpixels, where each superpixel contained 16 (i.e., 4x4) pixels. Ananalysis of variance technique was developed to analyze each superpixel with three baseline andthree follow-up images. The performance of the technique was tested with and without adjustmentfor spatial correlation of topographic values using computer simulations and with real data from anormal control subject and a patient with progressive glaucomatous disc change. RESULTS:Computer simulation with fixed population means and variance, and varying spatial correlationshowed a monotonically increasing number of superpixels with significant test results (falsepositives), with 20% false-positives when the spatial correlation was 0.8 (the approximate medianvalue in real patient data). The number of false-positive results was similar (17%) in serial imagesof a normal subject. When corrected for spatial correlation, the number of false-positives wasindependent of the level of spatial correlation and remained at the expected value of less than 5% inboth simulations and real data. Although the number of significant test results in the patient withprogressive glaucoma decreased after correction for spatial correlation, the change was readilyapparent. Statistical power to detect mean differences in topographic values ranging from 0.5 to 4.0SDs in computer simulation showed low power for changes of 1 SD or less, but increaseddramatically with larger changes. CONCLUSIONS: This technique has a high level of sensitivity todetect changes in the optic disc while maintaining a high level of specificity.

Am J Ophthalmol 2000 Feb;129(2):129-135Optical coherence tomography and scanning laser polarimetry in normal, ocularhypertensive, and glaucomatous eyes.Hoh ST, Greenfield DS, Mistlberger A, Liebmann JM, Ishikawa H, Ritch R.Department of Ophthalmology, The New York Eye and Ear Infirmary, New York, New York,USA.

PURPOSE: To evaluate the relationship between visual function and retinal nerve fiber layermeasurements obtained with scanning laser polarimetry and optical coherence tomography in amasked, prospective trial. METHODS: Consecutive normal, ocular hypertensive, and glaucomatoussubjects who met inclusion and exclusion criteria were evaluated. Complete ophthalmologicexamination, disk photography, scanning laser polarimetry, optical coherence tomography, andautomated achromatic perimetry were performed. RESULTS: Seventy-eight eyes of 78 patients (17normal, 23 ocular hypertensive, and 38 glaucomatous) were enrolled (mean age, 56.8+/-11.5 years;range, 26 to 75 years). Eyes with glaucoma had significantly greater neural network scores onscanning laser polarimetry and lower maximum modulation, ellipse modulation, and mean retinalnerve fiber layer thickness measured with optical coherence tomography compared with normal andocular hypertensive eyes, respectively (all P<.005). Significant associations were observed betweenneural network number (r = -.51, r = .03), maximum modulation (r = .39, r = -.32), ellipse

16

modulation (r = .36, r = -.28), and optical coherence tomography-generated retinal nerve fiber layerthickness (r = .68, r = -.59) and visual field mean deviation and corrected pattern standard deviation,respectively. All scanning laser polarimetry parameters were significantly associated with opticalcoherence tomography-generated retinal nerve fiber layer thickness. CONCLUSION: Opticalcoherence tomography and scanning laser polarimetry were capable of differentiating glaucomatousfrom nonglaucomatous populations in this cohort; however considerable measurement overlap wasobserved among normal, ocular hypertensive, and glaucomatous eyes. Retinal nerve fiber layerstructural measurements demonstrated good correlation with visual function, and retinal nerve fiberlayer thickness by optical coherence tomography correlated with retardation measurements byscanning laser polarimetry.

Acta Ophthalmol Scand 2000 Feb;78(1):9-13Comparability of three-dimensional optic disc imaging with different techniques. A studywith confocal scanning laser tomography and raster tomography.Gundersen KG, Heijl A, Bengtsson B.Department of Ophthalmology, Malmo University Hospital, Sweden. kg.gundersen@oftal.mas.lu.se

PURPOSE: We wanted to compare optic nerve head topography measurements and discriminationbetween normal and glaucomatous eyes with two entirely different three-dimensional optic discimaging techniques, confocal scanning laser tomography (Heidelberg Retina Tomograph,Heidelberg Engineering) and raster tomography (Glaucoma-Scope, Ophthalmic Imaging Systems).METHODS: Both eyes of 225 normal subjects and 229 eyes of 166 patients with glaucoma atdifferent stages were imaged with the Heidelberg Retina Tomograph and the Glaucoma-Scope.Optics discs were analysed in 15 degrees sectors around the circumference. Depth measurementswere calibrated on objects with known dimensions. RESULTS: We observed no significantdifferences in absolute measurements of maximum cup depth and cup area between the twoinstruments. We observed small differences in absolute measurements of disc anti rim area betweenthe two instruments. Discrimination between normal and glaucomatous eyes was close to identicalfor the two instruments. Both instruments had the same ability to distinguish glaucomatous regionalalterations of optic nerve head topography from normal disc configuration. CONCLUSION: Bothinstruments while using entirely different principles for three-dimensional optic disc imaging gavevery similar results. This correspondence of results implies that the same optic disc parameters canbe analysed, and the results interpreted similarly for both methods, and probably with other three-dimensional imaging instruments. It may also indicate that results of studies with one of theinstruments have general validity.

Concordance between results of optic disc tomography and high-pass resolution perimetry inglaucoma.Martin_LM; Lindblom_B; Gedda_UKJ Glaucoma, 2000 02, 9: 1, 28-33

PURPOSE: To evaluate concordance between results obtained with the Heidelberg RetinaTomograph (HRT) (Heidelberg Engineering GmbH, Heidelberg, Germany) and those obtained withthe high-pass resolution perimeter (HRP) in glaucoma diagnosis. METHODS: A total of 217patients from the glaucoma services at St. Erik Eye Hospital, Stockholm, Sweden (n = 107) andSahlgrenska University Hospital, Göteborg, Sweden (n = 110) were included in the study. Allpatients were examined because of known or suspected glaucoma in at least one eye. Theconventional indices presented by the instruments were used, i.e., glaucoma index from the HRT(negative values = abnormal, positive = normal) and combined deviation (upper normal limit 2.1dB) from the HRP. RESULTS: The concordance regarding the classification of normal or

17

glaucomatous by the two instruments was 71% (153/217 eyes). The HRT indicated glaucoma butHRP findings were normal in 47 patients, and the reverse occurred in 17 patients. There was asignificant difference in optic disc area between patients with abnormal HRT findings and normalHRP findings and in patients with normal HRT findings and abnormal HRP findings. Theconcordance could not be improved by adjusting for disc size. The correlation between combineddeviation on HRP and the HRT glaucoma index was r = -0.53. CONCLUSION: A significantcorrelation was found between the combined index given by HRP and the HRT glaucoma index in217 patients examined for known or suspected glaucoma. Discordant findings were observed in 64patients; in 22 this discordance was explained by the influence of disc size. No other reasons fordifferences in examination results could be detected.

Surv Ophthalmol 1999 Oct;44:S41-S53Quantitative morphologic and functional evaluation of the optic nerve head in chronic open-angle glaucoma.Bartz-Schmidt KU, Thumann G, Jonescu-Cuypers CP, Krieglstein GK.Department of Ophthalmology, University of Cologne, Germany.Ulrich.BartzSchmidt@unikoeln.de

Glaucoma leads to morphologic changes of the optic nerve head and to functional defects.Morphologic changes in the three-dimensional surface structure of the optic nerve head at itsentrance site into the globe can be examined by laser scanning tomography. The standard techniquefor evaluating functional defects in glaucoma is static computerized perimetry. We compared thesetwo techniques to determine which is more sensitive for follow-up of glaucomatous damage of theoptic nerve head. If decreased function is presumed to precede imminent cell death, visual fieldanalysis should be the more sensitive method, as cell death results in absolute defects of the visualfield. However, the neuronal networks do not necessarily function in this way. In the case of loss ofindividual elements in the neuronal network, the complex linkages, even at the retinal level, are ableto maintain functions and compensate for loss of function, which means that visual field defectswould not be prominent. If the damage increases with time and is accompanied by a progressiveloss of ganglion cells, however, compensation is eventually no longer possible, and the functionaldefects then become measurable by visual field analysis. Thus, morphologic absolute changes maybe more prominent than visual field defects in the early stages of glaucoma. To evaluate thequantitative relationship between morphometrically measurable defects of the optic nerve head andmeasurable functional defects, we first examined the visual field with static computerized perimetryand then evaluated the surface structure with a laser scanning tomograph in 90 patients with chronicopen-angle glaucoma, 10 patients with ocular hypertension, and 10 patients without any eyedisease. Based on the 95th percentile of the standardized rim/disk area ratio, we calculated therelative rim area loss and correlated this with the mean defect in visual field analysis. Thescatterplot shows an exponential curve. In the early stages of glaucoma, visual field defects wereless prominent than morphologic absolute changes; 40% of the neuroretinal rim area is lost byglaucomatous optic nerve damage before first defects in visual field analysis appear. In late stagesof glaucoma, changes in perimetry are more prominent than those observed with biomorphometry.These results show that in the follow-up of patients with early stages of glaucomatous damage,special attention should be given to morphologic absolute changes. In patients with advancedglaucoma, progress of the damage should be observed by repeated functional, rather thanmorphologic, examinations. It is important to keep in mind, however, that the sensitivity of anymethod is dependent on technology. One reason why functional tests may not be as sensitive asmorphologic examination in observing patients with early stages of glaucoma may simply be thatfunctional tests are not yet sensitive enough to detect early damage.

18

Surv Ophthalmol 1999 Oct;44:S33-S40Topographic analysis to discriminate glaucomatous from normal optic nerve heads with aconfocal scanning laser: new optic disk analysis without any observer input.Iester M, De Ferrari R, Zanini M.Department of Neurological and Visual Sciences, Ophthalmology B, University Eye Clinic ofGenoa, Italy.

PURPOSE: We evaluated the potential ability of a confocal scanning laser ophthalmoscope todifferentiate patients with normal visual fields from those with abnormal visual fields with an opticnerve head topographic map. PATIENTS AND METHODS: Twenty normal eyes with normalvisual fields, intraocular pressures of less than 22 mm Hg, and no family history of glaucoma and20 glaucomatous eyes with abnormal visual fields and open angles were selected. Glaucomatouseyes with advanced visual field damage were not included. One eye was chosen randomly fromeach patient. All eyes were examined with the Heidelberg Retina Tomograph (HRT [HeidelbergEngineering GMBH, Heidelberg, Germany]) and Humphrey Perimeter, program 30-2 (HumphreyInstruments, Inc., San Leandro, CA, USA). Topographic maps were analyzed with differentmethods based on contour lines, with use of a program able to differentiate glaucomatous fromnormal optic disks. Sensitivity, specificity, and diagnostic precision were calculated. RESULTS:The analysis had a sensitivity, specificity, and diagnostic precision of 80%, 100%, and 90%,respectively. CONCLUSION: With the topographic map data and this technique, the HRT'scapacity to differentiate normal optic disks from glaucomatous disks was improved. In addition,with this method, we avoided any subjective observer input in drawing the optic nerve head outline.

Ophthalmology 1999 Oct;106(10):2027-2032Heidelberg retina tomography and optical coherence tomography in normal, ocular-hypertensive, and glaucomatous eyes.Mistlberger A, Liebmann JM, Greenfield DS, Pons ME, Hoh ST, Ishikawa H, Ritch R.Department of Ophthalmology, The New York Eye and Ear Infirmary, New York 10003, USA.

PURPOSE: To evaluate optic disc and retinal nerve fiber layer (RNFL) appearance in normal,ocular-hypertensive, and glaucomatous eyes undergoing confocal scanning laser ophthalmoscopyand optical coherence tomography (OCT). DESIGN: Prospective, cross-sectional study.PARTICIPANTS: Seventy-eight eyes of 78 consecutive normal (n = 17), ocular-hypertensive (n =23), and glaucomatous subjects (n = 38) were enrolled. METHODS: Each patient underwentcomplete ophthalmic examination, achromatic automated perimetry, confocal scanning laserophthalmoscopy (Heidelberg Retinal Tomography [HRT]), and OCT. Topographic HRT parameters(disc area, cup-disc ratio, rim area, rim volume, cup shape measure, mean RNFL thickness, andcross-sectional area) and mean OCT-generated RNFL thickness were evaluated in each group.MAIN OUTCOME MEASURES: OCT and HRT assessment of optic disc and RNFL anatomy.RESULTS: OCT RNFL thickness showed no difference between normal and ocular-hypertensiveeyes (P = 0.15) but was significantly less in glaucomatous eyes (P < 0.001). HRT measurements ofrim area, cup-disc ratio, cup shape measure, RNFL thickness, and RNFL cross-sectional area weresignificantly less in glaucomatous eyes (all P < 0.005) and were correlated with mean OCT RNFLthickness (all P < 0.02). RNFL thickness using OCT or HRT was highly correlated with visual fieldmean defect during achromatic perimetry (P < 0.0001). CONCLUSION: Both HRT and OCT candifferentiate glaucomatous from nonglaucomatous eyes. RNFL thickness measurements using OCTcorrespond to disc topographic parameters using HRT.

Jpn J Ophthalmol 1999 Sep;43(5):410-414Scanning laser tomography to evaluate optic discs of normal eyes.

19

Nakamura H, Maeda T, Suzuki Y, Inoue Y.Eye Division of Olympia Medical Clinic, Tokyo, Japan.

PURPOSE: To investigate the effects of age, eye refraction, and disc area on topographicparameters of the optic nerve head in normal volunteers, using the Heidelberg Retina Tomograph.METHODS: Seventy-seven eyes of 77 normal volunteers were examined by scanning lasertomography. The topographic parameters analyzed were disc area, cup area, cup/disc area ratio, rimarea, cup volume, rim volume, mean cup depth, maximum cup depth, cup shape measure, heightvariation contour, mean retinal nerve fiber layer thickness (MnRNFLT), and retinal nerve fiberlayer (RNFL) cross-section area. The effect of age, refraction, and disc area on each parameter wasanalyzed by the multiple linear regression model. RESULTS: Significant declines in MnRNFLTand RNFL cross-section area were found with increasing age (P < .05). The mean cup depth andmaximum cup depth were significantly deeper in myopic subjects (P < .05). Large discs had largecup area, cup/disc area ratio, rim area, cup volume, mean cup depth, cup shape measure (P < .01),and maximum cup depth (P < .05). The MnRNFLT was smaller in large discs (P < .01). Rimvolume was unaffected by age, refraction, or disc area. CONCLUSIONS: The age, refraction, anddisc area were related to several optic disc parameters obtained by the Heidelberg RetinaTomograph. Because of these relationships, care should be taken to analyze the appearance of theoptic disc on the basis of these parameters in patients with glaucoma or other diseases. Rim volumeappears to be a good parameter for evaluating the optic disc without considering age, refraction, ordisc area.

Jpn J Ophthalmol 1999 Sep;43(5):392-397Influence of myopic disc shape on the diagnostic precision of the Heidelberg RetinaTomograph.Yamazaki Y, Yoshikawa K, Kunimatsu S, Koseki N, Suzuki Y, Matsumoto S, Araie M.Department of Ophthalmology, Nihon University School of Medicine, Tokyo, Japan.

PURPOSE: To investigate the diagnostic capability of a glaucoma diagnostic classification programfor the Heidelberg Retina Tomograph (HRT) in eyes with myopic disc shapes. METHODS: Sixty-six normal subjects (66 eyes) and 78 open-angle glaucoma patients (78 eyes) were enrolled. Theeyes were divided into two groups; those eyes with myopic and those with nonmyopic disc shapes.The classification was based on clinical judgment made after the examination of stereophotographsof the discs without considering the refractive errors. The agreement between the classificationprogram and the clinical diagnosis was evaluated for sensitivity, specificity, and diagnosticprecision. The influence of the disc shape on the HRT topographic parameters was evaluated.RESULTS: The sensitivity, specificity, and diagnostic precision of the HRT were 83%, 95%, and89% in eyes with nonmyopic disc shapes, but 71%, 96%, and 83% in those with myopic discshapes. Rim volume, height variation contour, mean retinal fiber nerve layer (RNFL) thickness, andRNFL cross-section area were significantly larger in eyes with myopic disc shapes than in eyes withnonmyopic discs, regardless of the clinical diagnosis. CONCLUSIONS: The classification programshould be modified to take into account the myopic disc shape in order to improve its capability tomake more accurate diagnosis of glaucoma possible.

Klin Monatsbl Augenheilkd 1999 Sep;215(3):182-185Initial clinical experiences with the Dresden 3D display in conjunction with the HeidelbergRetina Tomograph (HRT).Muller-Richter UD, Malig HJ, Schwerdtner A, Lang M, Hille K, Ruprecht KW.Augenklinik und Poliklinik, Universitat des Saarlandes, Homburg, Saar.

20

BACKGROUND: For years the Heidelberg Retina Tomograph has been an established method todiagnose early glaucomatous damages at the optic nerve head. The major difficulty consists indefining the outlayer of the optic nerve head in a 2-dimensional reflective or topographic picture. A3-dimensional presentation of the ocular fundus could ease the defining very much. The Dresden3D-display tested provides a true 3-dimensional presentation of the HRT-values measured.METHODS: For the study 5 groups of prediagnosed follow-up examinations were formed, which intheir course showed various progression. The examination firstly was carried out by manualdefining of the papilla contour on the Dresden 3D-display and secondly by the new automaticcontour-finding of the 3D-software. RESULTS: Through the 3-dimensional presentation a morecorrect position of the contour can be found when drawn manually. As a result some diagnoses ofthe 2-dimensional HRT-pictures had to be revised. The results proved considerable differencesbetween the automatic outlayer-finding and the probably real position of the papilla borders.CONCLUSION: The 3-dimensional presentation of the HRT-pictures represents an subjectiveimprovement regarding the accuracy of manual contour definition. In particular, the fact that it isfeasible to make the pictures rotate around the axes offers completely new insights to themorphology of the disc.

Ophthalmology 1999 Sep;106(9):1751-1755Optic disc topographic measurements after pupil dilation.Zangwill LM, Berry CC, Weinreb RN.Glaucoma Center and Diagnostic Imaging Laboratory, University of California San Diego, La Jolla92093-0946, USA. ZANGWILL@EYECENTER.UCSD.EDU

PURPOSE: To determine the effect of pupil dilation on topographic optic disc parameters measuredwith confocal scanning laser ophthalmoscopy. DESIGN: Prospective, comparative, observationalcase series. PARTICIPANTS: Thirty-eight subjects (25 glaucoma patients, 5 glaucoma suspects,and 8 normal subjects) representing a range of lens opacities participated in this study. METHODS:Topographic optic disc parameter measurements were obtained before and after pupil dilation witha confocal scanning laser ophthalmoscope (Heidelberg Retina Tomograph). Cataract severity wasmeasured with the LOCS III grading system. Image quality was assessed using the standarddeviation of the mean topography image and an image quality score. Multiple regression techniqueswere used to evaluate the effect of image quality, cataract density, and pupil size on the change intopographic parameters after dilation. MAIN OUTCOME MEASURES: Topographic optic discparameter measurements. RESULTS: With dilation, mean change in most topographic optic discparameters was not significantly different from zero. Changes in topographic optic nerveparameters tended to be relatively small when undilated images were of good quality and larger inimages of relatively poor quality. The strongest predictor of the absolute value of change intopographic optic disc parameters was the standard deviation of the undilated mean topographyimage. CONCLUSIONS: When confocal scanning laser ophthalmoscope images are of goodquality, topographic optic disc parameter measurements obtained with a dilated pupil are similar tothose obtained with an undilated pupil. However, caution should be exercised when interpretinginformation from poor quality confocal scanning laser ophthalmoscopic images.

Optom Vis Sci 1999 Aug;76(8):526-536New technologies for diagnosing and monitoring glaucomatous optic neuropathy.Zangwill LM, Chang CF, Williams JM, Weinreb RN.Glaucoma Center and Diagnostic Imaging Laboratory, Department of Ophthalmology, Universityof California, San Diego, La Jolla, California 92093-0946, USA.

21

BACKGROUND: Recently, instruments have been developed to provide real-time, quantitativemeasurements of the optic disc and retinal nerve fiber layer (RNFL) for use in glaucomamanagement. Our objective is to (1) provide an overview of two of these instruments, the confocalscanning laser ophthalmoscope (Heidelberg Retina Tomograph, HRT) and scanning laserpolarimeter (Nerve Fiber Analyzer, NFA) and (2) compare measurements obtained with theseinstruments to clinical features used in the diagnosis of glaucoma. METHODS: Twenty glaucomapatients, 4 normal subjects and 20 glaucoma subjects were included. All subjects had imagesobtained with the HRT and NFA, and RNFL and optic disc photography completed within 5 weeksof each other. The HRT results were compared with qualitative evaluation of stereophotographs ofthe optic disc, and NFA results were compared against a semi-quantitative RNFL photographseverity score. RESULTS: Twenty-five (57%) subjects had thinning of the neuroretinal rimidentified by evaluation of stereoscopic optic disc photographs. Despite overlap, HRTmeasurements of rim volume, rim area, and rim/disc ratio were significantly smaller in eyes withevidence of rim thinning than in eyes with no evidence of rim thinning. Moderate to severe RNFLdamage was detected by evaluation of photographs in 25 (57%) of subjects. NFA RNFL thicknessmeasures were smaller in eyes with moderate to severe RNFL damage than in relatively healthyeyes. CONCLUSIONS: Previous studies have documented the reproducibility of these instrumentsand suggested analytic techniques for improving their ability to differentiate between normal andglaucoma eyes. Our results indicate that despite overlap in values, these instruments providemeasurements that reflect clinically relevant features of the optic disc and RNFL. Whether thesetechnologies can improve our ability to detect glaucomatous progression over time needs to bedetermined with well-designed longitudinal studies and comparison with established diagnostictechniques for evaluating glaucomatous optic neuropathy.

Arch Ophthalmol 1999 Aug;117(8):1010-1013Optic nerve head morphologic characteristics in high-tension and normal-tension glaucoma.Iester M, Mikelberg FS.Department of Ophthalmology, University of British Columbia, Vancouver, Canada.

OBJECTIVES: To determine the morphometric parameters in high-tension glaucoma (HTG) andnormal-tension glaucoma (NTG) with a confocal scanning laser ophthalmoscope, and to determinethe relationship to disc size. METHODS: One hundred eighty-six patients with glaucoma wererecruited for this study. For each patient, only one eye was randomly chosen. Patients with NTGand HTG were classified using untreated intraocular pressure (IOP) as the variable; the NTG grouphad IOP less than 22 mm Hg during a diurnal tension curve, while patients with HTG had IOPgreater than 21 mm Hg in at least 3 measurements. All the patients were examined with Humphreyperimeter program 30-2 and a Heidelberg Retina Tomograph. Findings were assessed by t test.Patients were then divided by disc area size into 3 subgroups: small discs with an area less than 2mm2, midsized discs with an area of 2 to 3 mm2, and large discs with an area greater than 3 mm2.RESULTS: One hundred thirty-two HTG eyes and 50 NTG eyes were assessed. Four eyes wereexcluded because they were classified as having secondary glaucoma. No significant differenceswere found between HTG and NTG eyes for any Heidelberg Retina Tomograph morphometricparameters, even when patients were divided into subgroups. CONCLUSION: No differences wereapparent between HTG and NTG in morphometric parameters as measured by scanning laserophthalmoscopy.

Klin Monatsbl Augenheilkd 1999 Jun;214(6):378-385Laser scanning topography and polarimetry with implantation of intraocular lenses beforeand after cataract surgery.Kremmer S, Pflug A, Heiligenhaus A, Fanihagh F, Steuhl KP.

22

Abteilung fur Erkrankungen der vorderen, Universitats-Augenklinik Essen.

BACKGROUND: In the last years, scanning laser measurements were established in glaucomadiagnostics. Techniques of special interest are scanning laser topometry (SLT) for exactmeasurements of the optic disc and its cup and scanning laser polarimetry (SLP) for preciseassessment of the retinal nerve fiber layer thickness. As glaucoma patients often suffer from acataract, too, and a trabeculectomy additionally favors the advance of lens opacities, in the followup of glaucoma patients cataract surgery is often necessary. PATIENTS AND METHODS: Theinfluence of cataract surgery in phacotechnique with intraocular lens implantation (31 PMMA-IOLs, Pharmacia/Upjohn, model 811 B, and 25 HEMA/MMA-IOLs, Technomed, Memory Lens)on SLT and SLP was evaluated before and 3 to 4 weeks after cataract surgery in 56 eyes ofotherwise healthy patients. Lens opacities were classified according to LOCS III. For SLT, weapplied a TopSS, and for SLP a Nerve Fiber Analyzer II and a GDx (LDT, USA). RESULTS: Ourresults show that SLT and SLP are mostly performable at lens opacities with visual acuityreductions down to 0.16. In SLT, we usually found no big differences in the assessed parametersbefore and after cataract surgeries with IOL implantation. Standard deviations between three singlemeasurements were mostly smaller postop. In SLP, nerve fiber layer patterns were very similarbefore and after cataract surgeries with IOL implantation whereas total nerve fiber layer thicknessvalues postoperatively were slightly higher. CONCLUSIONS: Our results indicate that cataractsurgeries with IOL-implantation have only mild influence on SLT and SLP. These findings seem tobe of clinical interest especially in the follow up of glaucoma patients.

Ophthalmology 1999 Jun;106(6):1147-1151Comment in: Ophthalmology. 2000 Mar;107(3):407Longitudinal changes in optic disc topography of adult patients after trabeculectomy.Topouzis F, Peng F, Kotas-Neumann R, Garcia R, Sanguinet J, Yu F, Coleman AL.Jules Stein Eye Institute and Department of Ophthalmology, University of California Los Angeles,School of Medicine 90095-7004, USA.

OBJECTIVE: To study longitudinal changes in optic disc topography after trabeculectomy in adultpatients. DESIGN: Prospective case series. PARTICIPANTS: Twenty-five eyes of 25 patientsundergoing trabeculectomy were enrolled. INTERVENTION: Images of the optic disc wereobtained preoperatively and approximately 2 weeks, 4 months, and 8 months after surgery by use ofa confocal scanning laser ophthalmoscope (Heidelberg Retina Tomograph). MAIN OUTCOMEMEASURES: The topographic optic disc parameters (cup volume, cup area, rim volume, rim area,cup-disc area ratio, mean cup depth, maximum depth, cup shape, and height variation contour) weremeasured automatically for each image with the Heidelberg Retina Tomograph Software (version1.11). RESULTS: Approximately 2 weeks after surgery, the mean preoperative intraocular pressure(IOP) of 19.3 mmHg (SD, 6.4 mmHg) decreased to 6.0 mmHg (SD, 3.6 mmHg), cup volume andmean cup depth decreased, height variation contour increased, and the cup shape parameter becamemore negative. Approximately 4 months after surgery, mean IOP was 9.7 mmHg (SD, 4.2 mmHg),and the only statistically significant change from preoperative values of optic disc parameters wasin the cup shape measure. Approximately 8 months after surgery, there was no statisticallysignificant change in any of the optic disc parameters compared with preoperative values, althoughIOP was 10.4 mmHg (SD, 5.9 mmHg). CONCLUSIONS: Changes in the optic disc that may bepresent 2 weeks after a trabeculectomy do not appear to persist 4 and 8 months later in eyes withadvanced glaucomatous optic nerve damage, except for cup shape, which was different frompreoperative values at 4 months but not at 8 months.

Ophthalmology 1999 May;106(5):1013-1018

23

Reversal of optic disc cupping after glaucoma surgery analyzed with a scanning lasertomograph.Lesk MR, Spaeth GL, Azuara-Blanco A, Araujo SV, Katz LJ, Terebuh AK, Wilson RP, MosterMR, Schmidt CM.William and Anna Goldberg Glaucoma Service, Wills Eye Hospital, Jefferson Medical College,Thomas Jefferson University, Philadelphia, Pennsylvania 19107-5598, USA.

OBJECTIVE: To detect and quantitate changes in optic nerve morphology after glaucoma surgeryusing the Heidelberg Retina Tomograph (HRT, Heidelberg Instruments, Heidelberg, Germany).DESIGN: Nonconsecutive observational case series. PARTICIPANTS AND INTERVENTION:The authors prospectively enrolled 21 adult patients undergoing incisional glaucoma surgery forprogressive glaucoma damage. Quantitative analysis of the optic nerve head by scanning lasertomography and automated perimetry were performed before and after glaucoma surgery. MAINOUTCOME MEASURES: Changes in optic nerve parameters were subjected to linear regressionanalysis with respect to percent of postoperative reduction of intraocular pressure (IOP), as well aswith respect to age, refraction, preoperative cup:disc ratio, and change in visual field parameters.RESULTS: Seventeen patients had pre- and postoperative images suitable for analysis. Mean IOP atthe time of image acquisition before surgery was 30.5+/-12 mm Hg, and after surgery 11.8+/-5.2mm Hg (mean follow-up, 26+/-7 weeks). Eleven of 13 (85%) patients having IOP reduction ofgreater than 40% showed improvement in optic disc parameters. All four patients with less than25% reduction in IOP showed worsening of most parameters. Changes in optic disc parameterswere highly correlated with percent IOP reduction and with age. The parameters in which changemost strongly correlated with percent change of IOP were cup area, rim area, cup:disc ratio, andmean cup depth (each, P<0.005). The age of the patient correlated highly with change in maximumcup depth (P<0.005). Refraction and clinically determined cup:disc ratio correlated poorly withchanges in measured optic disc parameters. Clinical improvement in visual fields was correlatedwith the degree of improvement of cup:disc ratio (P = 0.025). CONCLUSION: Most patientsshowing a 40% lowering of IOP after glaucoma surgery show improved optic nerve morphology asmeasured by the HRT. The amount of improvement correlated highly with the percent reduction ofIOP.

Ophthalmologica 1999;213(4):219-223Asymmetry in intraocular pressure and retinal nerve fiber layer thickness in normal-tensionglaucoma.Gugleta K, Orgul S, Flammer J.University Eye Clinic, Basel, Switzerland.

The etiology of glaucoma is most probably multifactorial. This study intended to investigate theasymmetry in intraocular pressure (IOP) and that in retinal nerve fiber layer (RNFL) thickness innormal-tension glaucoma patients. Two diurnal tension curves, obtained within 3 months andcounting at least five IOP readings each, including an early morning IOP measurement uponawaking, were obtained in 15 normal-tension glaucoma patients. None of the patients received IOP-lowering therapy. IOP asymmetry was present in at least three readings and was always in the samedirection. The optic nerve was imaged in both eyes in each patient by means of confocal scanninglaser ophthalmoscopy (Heidelberg Retina Tomograph). The interocular difference in RNFLthickness and the RNFL cross-sectional area were correlated with the interocular difference in IOPby means of Spearman's rank correlation factor. Nine female and 6 male normal-tension glaucomapatients (mean +/- SD age was 62. 4 +/- 16.9 years) were included in this study. Interocular IOPasymmetry varied between 0.30 and 4 mm Hg. Strong negative correlations were found betweeninterocular asymmetry in IOP and interocular asymmetry in RNFL thickness asymmetry (R = -0.652, p = 0. 0083) and interocular asymmetry in RNFL cross-sectional area (R = -0. 702, p =

24

0.0034). The present results demonstrate for the first time a more marked thinning of theneuroretinal nerve fiber layer in the eye with the higher IOP in normal-tension glaucoma patients.

J Glaucoma 1999 Apr;8(2):99-104Agreement in assessing glaucomatous discs in a clinical teaching setting with stereoscopic discphotographs, planimetry, and laser scanning tomography.Hatch WV, Trope GE, Buys YM, Macken P, Etchells EE, Flanagan JG.School of Optometry, University of Waterloo, Canada.

PURPOSE: Agreement between three observers--two recently trained fellows and their supervisor--was measured using estimations of cup/disc ratio from stereoscopic optic nerve head photographsand planimetric measurements of cup/disc ratio. Agreement between the clinicians' planimetricmeasurements of cup/disc ratio and laser scanning tomographic measurements of cup/disc ratio alsowas assessed. METHODS: From 16 stereoscopic optic nerve head photographs of 16 subjects, thethree observers performed clinical estimations of horizontal and vertical cup/disc ratios andplanimetric measurements of cup/disc ratios. Interobserver agreement was measured usingintraclass correlation coefficients (ICCs). Agreement between the planimetric cup/disc ratios andlaser scanning tomographic cup/disc ratios obtained with the Heidelberg Retina Tomograph (HRT;Heidelberg Engineering, Heidelberg, Germany) also was measured using ICCs. The differencebetween the planimetric and HRT cup/disc ratios was calculated. RESULTS: The agreementbetween observers for clinical estimations from stereoscopic optic nerve head photographs (ICC =0.74 horizontally and 0.83 vertically) was substantial. Agreement between the observers'planimetric measurements of cup/disc ratio was substantial (ICC = 0.79). Agreement between HRTcup/disc ratio and each observer's planimetric cup/disc ratio was moderate (ICC = 0.57-0.65), withlarge confidence intervals. The cup/disc ratio measured with HRT was an average of 0.07 to 0.11larger than the planimetric cup/disc ratio. CONCLUSION: Substantial agreement betweenobservers can be achieved when estimating cup/disc ratio with stereoscopic optic nerve headphotographs and with planimetric measurements of cup/disc ratios, provided there is a standardprotocol and sufficient training period. Good agreement is critical in a teaching institution to ensureaccurate follow-up care of patients with glaucoma, especially if patients are examined by differentclinicians. Laser scanning tomography is a more repeatable and objective method, which mayprovide further standardization of optic nerve head assessments. Future studies will determine thereference plane that optimizes agreement between the HRT findings and each clinician'sestimations.

J Glaucoma 1999 Apr;8(2):105-110Agreement of measurement of parapapillary atrophy with confocal scanning laserophthalmoscopy and planimetry of photographs.Kono Y, Jonas JB, Zangwill L, Berry CC, Weinreb RN.Glaucoma Center, University of California at San Diego, La Jolla 92093-0946, USA.

PURPOSE: To evaluate whether parapapillary atrophy can be measured interactively usingconfocal scanning laser ophthalmoscopy. METHODS: For 36 patients with open-angle glaucoma orsuspected of having glaucoma, confocal scanning laser ophthalmoscopy of the optic nerve head wasperformed using the Heidelberg Retina Tomograph (HRT; Heidelberg Engineering, Heidelberg,Germany). Alpha and beta zones of parapapillary atrophy were plotted independently by twoexaminers on HRT images before and after reviewing optic disc photographs. These data werecompared with planimetric measurements obtained from analyzing the disc photographs.RESULTS: Before viewing the disc photographs, assessment using the HRT images correlatedbetter with the beta zone than alpha zone planimetric measurements. If the HRT images were

25

evaluated while simultaneously viewing disc photographs, correlation coefficients increased forboth examiners 1 and 2. Interobserver and intraobserver reliability were 0.431 and 0.802,respectively, for alpha zone, and 0.882 and 0.948, respectively, for beta zone. CONCLUSION:Parapapillary atrophy can be estimated with confocal scanning laser ophthalmoscopy. Correlationwith planimetric measurements is best if conventional optic disc photographs are simultaneouslyviewed. Intraobserver and interobserver reliability are higher for beta zone than for alpha zone.

Br J Ophthalmol 1999 Mar;83(3):299-304Preperimetric glaucoma diagnosis by confocal scanning laser tomography of the optic disc.Mardin CY, Horn FK, Jonas JB, Budde WM.Department of Ophthalmology and Eye Hospital, Friedrich-Alexander-University, Erlangen-Nurnberg, Germany.

AIM: To evaluate the ability of confocal scanning laser tomography of the optic nerve head todetect glaucomatous optic nerve damage in ocular hypertensive eyes without visual field defects.METHODS: The study included 50 normal subjects, 61 glaucoma patients with glaucomatouschanges in the optic disc and visual field, and 102 "preperimetric" patients with increasedintraocular pressure, normal visual fields, and glaucomatous appearance of the optic disc asevaluated on colour stereo optic disc photographs. For all individuals, confocal scanning lasertomographs of the optic nerve head were taken using the Heidelberg retina tomograph (HRT;software 2.01). RESULTS: Almost all investigated HRT variables varied significantly (p < 0.05)between the normal eyes and preperimetric glaucoma eyes with pronounced overlap between thetwo study groups. Corresponding to the overlap, sensitivity and specificity values were relativelylow when HRT variables were taken to differentiate between normal and preperimetric glaucomaeyes. At a given specificity of 95% highest sensitivities were found for the variables "rim area in thesuperior disc sector" (24.8%), "nerve fibre layer thickness in the inferior disc sector" (26.5%), and"rim volume in the superior disc sector" (25.5%). A multivariate approach increased sensitivity to42.2% at a given specificity of 95%. For the glaucoma group highest sensitivity values werereached by rim volume in the superior disc sector (73.8%) and rim area (72.1%); the multivariateapproach reached 83.6%. CONCLUSIONS: Owing to pronounced overlapping between the groups,confocal scanning laser tomography of the optic nerve head has relatively low diagnostic power todifferentiate between normal eyes and preperimetric glaucoma eyes. One of the reasons may be thebiological interindividual variability of quantitative optic disc variables.

Br J Ophthalmol 1999 Mar;83(3):295-298Comparison between laser scanning tomography and computerised image analysis of theoptic disc.Azuara-Blanco A, Spaeth GL, Nicholl J, Lanzl IM, Augsburger JJ.Department of Ophthalmology Queen's Medical Centre, University of Nottingham.

AIMS: To study the interchangeability of the measurements of the optic disc topography obtainedby one computerised image analyser and one confocal laser tomographic scanner. METHODS: Oneeye of 28 patients with glaucoma or glaucoma suspects was studied. All cases had simultaneousstereoscopic disc photographs taken with the fundus camera Topcon TRC-SS and optic discexamination with the Heidelberg retina tomograph (HRT) during the same visit. The optic discphotographs were digitised and analysed with the Topcon ImageNet (TI) system. Three variables ofthe optic disc topography provided by the TI and the HRT were compared—cup volume (CV), rimarea (RA), and cup area to disc area ratio (CA/DA). RESULTS: The mean values of CV and RAprovided by the TI (0.52 (SD 0.32) mm3 and 1.58 (0.39) mm2, respectively) were greater (p < 0.01)than the mean values of CV and RA determined by the HRT (0.32 (0.25) mm3, and 1.33 (0.47)

26

mm2, respectively). The mean value of CA/DA provided by the TI (0.42 (0.14)) and the HRT (0.42(0.18)) was similar (p = 0.93). Correlation coefficients between measurements obtained by the twomethods ranged from 0.53 to 0.73. CONCLUSION: There was a significant discrepancy in themeasurements of rim area and cup volume of the optic disc obtained by a computerised imageanalyser and a laser scanning tomograph.

Am J Ophthalmol 1998 Dec;126(6):763-771Patterns of optic disk damage in patients with early focal visual field loss.Emdadi A, Zangwill L, Sample PA, Kono Y, Anton A, Weinreb RN.Glaucoma Center and Research Laboratories, University of California, San Diego, La Jolla 92093-0946, USA.

PURPOSE: To study the patterns of structural damage of the optic disk in patients with early focalvisual field loss using a confocal scanning laser ophthalmoscope. METHODS: Thirty-nine subjectswith repeatable early focal visual field loss were included. The Heidelberg Retina Tomograph(Heidelberg Engineering, Heidelberg, Germany) was used to obtain topographic optic diskmeasurements. For analysis of structural damage, the topographic measurements were divided into36 10-degree sectors. Sector analysis was performed using sector rim area to sector disk area ratio.Patients were assigned to one of three groups based on the measurement of the optic disk damage:(1) diffuse disk damage; (2) focal disk damage; or (3) no detectable disk damage. RESULTS:Approximately half of the patients with early focal glaucomatous visual field loss showed diffuseoptic disk damage, one quarter to one third had focal damage, and one sixth had no detectabledamage. Optic disk area was smallest in the no-detectable-damage group (1.71 + 0.19 mm2),followed by the focal-damage group (2.06 + 0.54 mm2), and was largest in the diffuse damagegroup (2.29 + 0.48 mm2; P = .22). CONCLUSION: In patients with early focal glaucomatous visualfield loss, observable optic disk damage can be diffuse, focal, or undetectable. The HeidelbergRetina Tomograph may be capable of detecting different patterns of diffuse or focal structuraldamage.

Ophthalmology 1998 Dec;105(12):2186-2192Magnification characteristics of fundus imaging systems.Rudnicka AR, Burk RO, Edgar DF, Fitzke FW.Applied Vision Research Centre, City University, London, England.

OBJECTIVE: To compare the magnification properties of 11 different fundus cameras (including 1stereo fundus camera), a Rodenstock (infrared) scanning laser ophthalmoscope (SLO), theHeidelberg Laser Tomographic Scanner (LTS), and the Heidelberg Retina Tomograph (HRT).DESIGN: A cross-sectional study of the relationship between the true size of a fundus feature andits photographic-computer image in 14 different fundus imaging devices. This relationship wasevaluated for each instrument using a model eye adjusted for axial ametropia between +11 diopter(D) and -14 D. To simulate refractive ametropia, the "crystalline lens" was removed to render themodel eye aphakic, and the axial length was adjusted to give aphakic ametropia from emmetropia to+20 D. MAIN OUTCOME MEASURES: A correction factor (p) was calculated for eachinstrument, which can be used in calculations for determining true retinal size. RESULTS: Thefollowing were found to be of telecentric construction, Zeiss Oberkochen (WS240 Heidelberg),Zeiss Oberkochen (UK), Zeiss Oberkochen (Cologne), Nikon NF505, Kowa RCXV, SLO prototype(UK), LTS, and the HRT, and each exhibited a constant relationship between p and degree ofametropia of the model eye. The Canon CF6OU, Canon CF6OS, Canon CR4-45NM, Nidek 3-DX,Olympus GRCW, and Carl Zeiss Jena Retinophot were found not to be telecentric and exhibited alinear relationship between p and degree of ametropia of the model eye. For all instruments, p

27

remained unchanged for axial and refractive ametropias of the same degree. CONCLUSIONS: Thestudy has shown that not all fundus imaging systems are telecentric, so the use of a singlemagnification correction value may not be appropriate. These findings have important implicationsfor the way in which true retinal size calculations are performed. Examples are given to show howthe tabulated values of correction factors can be used for both telecentric and nontelecentriccameras in image size calculations.

Eye 1998;12( Pt 4):686-690The correlation of the visual field with scanning laser ophthalmoscope measurements inglaucoma.Tole DM, Edwards MP, Davey KG, Menage MJ.Eye Department, Clarendon Wing, Leeds General Infirmary, UK.

PURPOSE: To assess the relationship between Humphrey visual field data and optic disctopographical data collected by the Heidelberg Retina Tomograph (HRT) scanning laserophthalmoscope in chronic glaucoma patients. METHODS: The mean deviation (MD) andcorrected pattern standard deviation (CPSD) from Humphrey visual fields of 106 eyes of 106patients with glaucoma were analysed for correlation with the multiple topographical measurescalculated by the HRT. RESULTS: Significant correlations were found between MD of the visualfield and several optic disc measurements. These included neuroretinal rim volume, mean nervefibre layer thickness and cross-sectional area, and the cup shape measure. CPSD correlatedsignificantly only with mean nerve fibre layer cross-sectional area. This pattern was common to thewhole circumference of the disc with the exception of the directly temporal segment.CONCLUSION: Optic disc topography performed by HRT reflects the optic disc pathology incorrelation with perimetry.

Br J Ophthalmol 1998 Oct;82(10):1112-1117Laser scanning tomography of localised nerve fibre layer defects.Burk RO, Tuulonen A, Airaksinen PJ.Department of Ophthalmology, University of Heidelberg, Germany.

AIMS: Retinal nerve fibre layer photography is a well established method to qualitatively documentearly structural changes which might be induced by primary open angle glaucoma. The aim was toanalyse localised retinal nerve fibre layer (RNFL) defects in a new quantitative way with respect tosurface topography, defect width, and surface reflectivity by means of the technique of confocalscanning laser tomography. METHODS: 12 eyes of 12 patients with a localised RNFL defectdocumented in RNFL photographs and a normal appearance of the optic disc were enrolled in thestudy. Using confocal laser scanning tomography (Heidelberg retina tomograph, HRT) a series of32 optical section images from different focal planes of the retina at the site of the RNFL defectswere obtained. The optical section images, the reflectivity images, and the topographic images wereanalysed regarding the visibility of the RNFL defects. The mean surface height and the reflectanceat the sites of the RNFL damage were measured and compared with the adjacent apparently normalretina. The width of the RNFL defect at 1 mm distance from the disc border was evaluated.RESULTS: RNFL defects could be detected in nine of 12 reflectivity images (75%). Single opticalsection images displayed the RNFL defects in 12 of 12 eyes. The defect width ranged from 0.11 to1.0 mm. In six of 12 eyes a surface depression (34 (SD 5) microns; range 21-47 microns) waspresent. The reflectance ratio ranged from 0.68 to 0.94 at the site of the RNFL defect. In eyes with aglaucomatous scotoma in a 6 degrees grid visual field (VF), the defect width was at least 0.25 mm.Surface depression and low reflectance ratio were found irrespective of the presence of a scotoma inthe 6 degrees grid VF. CONCLUSION: The majority of localised RNFL defects can be detected in

28

reflectivity images from laser scanning tomograms. Localised RNFL defects may be differentiatedaccording to surface topography into those with and those without a measurable surface depression.A small but deep RNFL defect is not necessarily associated with a scotoma in routine 6 degrees gridVF static perimetry.

Curr Eye Res 1998 Sep;17(9):903-916Study of regional deformation of the optic nerve head using scanning laser tomography.Yan DB, Flanagan JG, Farra T, Trope GE, Ethier CR.Department of Ophthalmology, University of Toronto, Ontario, Canada.

PURPOSE: Previous studies have suggested that IOP-induced deformation of the optic nerve head(ONH) at the level of the lamina cribrosa may contribute to axonal damage in glaucomatous opticneuropathy. Our purpose was to introduce a novel enucleated eye model for characterizing acuteIOP-induced changes in ONH topography, and to develop improved analytical methods fordetection of regional topographic change in the ONH. METHODS: Using a specially designedexperimental apparatus, enucleated human eyes were progressively pressurized to 5, 15, 30, and 50mmHg. Seven topographic images of the optic disc were taken at each pressure by a scanning lasertomographer (Heidelberg Retina Tomograph-HRT). The dependence of ONH topography on IOPwas quantified for the entire nerve using standard HRT indices of ONH topographic change. Thesupero-inferior and nasal-temporal hemifields were also analyzed. A new method of analysis wasdeveloped which computes the location of the point of maximum slope within a 10 degrees sectorof the ONH, as well as the magnitude of this slope. This method, termed "Inflection PointAnalysis," was designed to be robust to the potential artefacts of image translation, reference planelocation, and the subjective determination of ONH limits. RESULTS: The results of three eyes arepresented to illustrate the techniques. In our enucleated eye model, average ONH depthprogressively increased with IOP, showing a maximum average posterior displacement of 36microm as IOP was changed from 5 to 50 mmHg. Significant regional variability in ONHdisplacement was observed, which both Inflection Point Analysis and standard HRT parameterswere able to detect. Inflection point analysis showed several advantages over standard HRTparameters: it was insensitive to artefacts due to tilt, was able to objectively delineate the boundarybetween the optic cup and neuroretinal rim, and was able to sensitively track changes in the locationof this margin. CONCLUSIONS: Scanning laser tomography is capable of detecting regionalvariation in the deformation of the ONH in response to acute changes in IOP. Our enucleated eyemodel and Inflection Point Analysis are promising tools for basic studies of ONH deformation inresponse to IOP. More extensive studies of both enucleated and in vivo eyes are required todetermine the potential of Inflection Point Analysis for studying and tracking the progression ofglaucomatous optic neuropathy.

Ophthalmology 1998 Aug;105(8):1557-1563Identification of early glaucoma cases with the scanning laser ophthalmoscope.Wollstein G, Garway-Heath DF, Hitchings RA.Glaucoma Unit, Moorfields Eye Hospital, London, England.

PURPOSE: This study aimed to define the confocal laser scanning ophthalmoscope (HeidelbergRetina Tomograph [HRT]) parameters that best separate patients with early glaucoma from normalsubjects. STUDY DESIGN: A cross-sectional study. PARTICIPANTS: A total of 80 normalsubjects and 51 patients with early glaucoma participated (average visual field mean deviation = -3.6 dB). INTERVENTION: Imaging of the optic nerve head with the HRT and analysis usingsoftware version 1.11 were performed. MAIN OUTCOME MEASURES: The relation betweenneuroretinal rim area and optic disc area, and cup-disc area ratio and optic disc area, was defined bylinear regression of data derived from the normal subjects. The normal ranges for these two

29

parameters were defined by the 99% prediction intervals of the linear regression between theparameter and optic disc area, for the whole disc, and for each of the predefined segments. Normalsubjects and patients were labeled as abnormal if the parameter for either the whole disc or any ofthe predefined segments was outside the normal range. The sensitivity and specificity values of themethod were calculated. RESULTS: The highest specificity (96.3%) and sensitivity (84.3%) valuesto separate normal subjects and those patients with early glaucoma were obtained using the 99%prediction interval from the linear regression between the optic disc area and the log of theneuroretinal rim area. Similar specificity (97.5%) and lower sensitivity (74.5%) values wereobtained with the 99% prediction interval derived from regression between the disc area and cup-disc area ratios. Poor separation between groups was obtained with the other parameters.CONCLUSIONS: The HRT, using the technique of linear regression to account for the relationshipbetween optic disc size and rim area or cup-disc area ratio, provides good separation betweencontrol subjects and patients with early glaucoma in this population.

Nippon Ganka Gakkai Zasshi 1998 Jun;102(6):378-382Use of a scanning laser tomograph to evaluate the optic disc of the normal eyes.Nakamura H, Maeda T, Suzuki Y, Inoue Y.Eye Division of Olympia Medical Clinic, Tokyo, Japan.

We evaluated the optic disc in 77 eyes of 77 normal volunteers using a scanning laser tomograph(Heidelberg Retina Tomograph: HRT, version 1.11). Particular attention was paid to age, refractiveerror, and disc size. The topographic parameters included: cup area, C/D area ratio, rim area, cupvolume, rim volume, mean cup depth, maximum cup depth, cup shape measure, height variationcontour, mean RNFL thickness, and RNFL cross section area. There was a significant decline inmean RNFL thickness and RNFL cross section area with increase in age (p < 0.05). The mean andmaximum cup depths were significantly deeper in myopic eyes (p < 0.05). Large discs had largevalues of cup area, C/D area ratio, rim area, cup volume, mean cup depth, cup shape measure (p <0.01), and maximum cup depth (p < 0.05). Large discs had small values of mean RNFL thicknessand RNFL cross section area. Rim volume was independent of age, refractive error, or disc area.

Br J Ophthalmol 1998 Apr;82(4):362-366Comparison of measurements of neuroretinal rim area between confocal laser scanningtomography and planimetry of photographs.Jonas JB, Mardin CY, Grundler AE.Department of Ophthalmology and Eye Hospital, Friedrich-Alexander-University, Erlangen-Nurnberg, Germany.

BACKGROUND: To compare neuroretinal rim area measurements by confocal scanning lasertomography and planimetric evaluation of optic disc photographs. METHODS: For 221 patientswith primary and secondary open angle glaucoma, 72 subjects with ocular hypertension, and 139normal subjects, the optic disc was morphometrically analysed by the confocal scanning lasertomograph HRT (Heidelberg retina tomograph) and by planimetric evaluation of stereo colouroptic disc photographs. RESULTS: Absolute rim area and rim to disc area were significantly (p <0.0001) larger with the HRT than with planimetric evaluation of photographs. Differences betweenthe two methods were significantly (p < 0.01) larger in normal eyes with small cupping than innormal eyes with large cupping, and differences were significantly (p < 0.01) larger inglaucomatous eyes with marked nerve damage than in glaucomatous eyes with moderate nervedamage. Coefficients of correlations between rim measurements of both methods were R2 = 0.60for rim to disc area and R2 = 0.33 for absolute rim area. Planimetric measurements of rim areacorrelated significantly (p < 0.05) better than HRT determinations of rim area with mean visual

30

field defect and retinal nerve fibre layer visibility. CONCLUSIONS: Measurements of absolute rimarea and rim to disc area are significantly larger with the HRT compared with planimetry of discphotographs. Differences between both methods depend on disc area, cup size and glaucoma stage.The reason may be that the HRT measures the retinal vessel trunk as part of the neuroretinal rim.The differences between both methods, which should be taken into account if disc measurementsperformed by both methods are compared with each other, may not influence the main advantage ofthe HRT--that is, morphological follow up examination of patients with glaucoma.

J Glaucoma 1998 Apr;7(2):121-127Detection of early glaucomatous structural damage with confocal scanning laser tomography.Bathija R, Zangwill L, Berry CC, Sample PA, Weinreb RN.Department of Ophthalmology, University of California, San Diego, La Jolla 92093-0946, USA.

PURPOSE: The authors determine which optic disc topographic parameters obtained by theHeidelberg Retina Tomograph (HRT, Heidelberg Engineering, Heidelberg, Germany) are mostuseful in detecting individuals with early glaucomatous visual field loss. METHODS: Ninety-nineeyes of 49 healthy individuals and 50 age-matched individuals with early glaucomatous visual fieldloss were included. Three images were obtained and the mean topography image was created andused in the analyses. The HRT discriminant analysis function (software version 2.01) was appliedand compared to the Fisher linear discriminant function developed in this population. Analysis wasrepeated after stratifying by disc area (< 2 mm2 or 2-3 mm2). RESULTS: There were statisticallysignificant differences between the healthy and glaucomatous groups for all optic disc topographicparameters (p < 0.05) measured. These differences remained after the analysis was repeatedcontrolling for disc size, except for height variation contour. Applying the HRT discriminantfunction to this study population resulted in sensitivity and specificity of 62% and 94%,respectively. The sensitivity was 83% while specificity remained high (91%) for larger disc sizes.Using this data, additional discriminant functions that differentiated similarly between the twogroups were found. The best formula used cup-shape measure (third moment), rim area, heightvariation contour, and retinal nerve fiber layer thickness and had a sensitivity and specificity of 78%and 88%, respectively. CONCLUSIONS: Several different discriminant analysis formulas arecapable of detecting early glaucomatous visual field loss in a comparable manner. Thecharacteristics of the study population are likely to influence the discriminating power of thesevarious formulas.

Ophthalmologica 1998;212(2):95-98Reproducibility of optic disk topographic measurements with the Topcon ImageNet and theHeidelberg Retina Tomograph.Azuara-Blanco A, Harris A, Cantor LB.Department of Ophthalmology, Indiana University, School of Medicine, Indianapolis, USA.

OBJECTIVE: To compare the reproducibility of optic disk measurements provided by an imageanalyzer and a scanning laser tomograph. METHODS: Ten images of the same eye of 10 normalvolunteers were taken with the Heidelberg Retina Tomograph and with the Topcon ImageNet.Intraclass correlation coefficient (ICC) and coefficient of variation (CV) were used to evaluate thereproducibility of the measurements. RESULTS: Eleven parameters were analyzed with the TopconImageNet. Six parameters (55%) had ICC greater than 90%. Four parameters (36%) had CV lessthan 10%. Twelve parameters were evaluated with the Heidelberg Retina Tomograph. Nineparameters (75%) had ICC over 90%. Nine parameters (75%) had CV less than 10%.CONCLUSION: Both systems provided reproducible data. The optic disk parameters provided by

31

the Heidelberg Retina Tomograph had a better reproducibility than those obtained from the TopconImageNet.

Klin Monatsbl Augenheilkd 1998 Feb;212(2):74-79Can the extent of glaucoma damage be assessed by measuring the asymmetry of theperipapillary height profile between the upper and lower retinal half? A clinical study withthe Heidelberg Retina Tomograph.Serguhn S, Gramer E.Universitats-Augenklinik Ulm.

BACKGROUND: Peripapillary height measurements are possible using 2 different reference planesof the Heidelberg-Retina-Tomograph. It is not tested yet, whether the extent of glaucoma damageshould be better quantified using reference plane 1 or 2. PATIENTS AND METHODS: In 32 eyesof 32 glaucoma patients with a defined up-down asymmetry of visual field loss is tested I.) if thereis a significant correlation between peripapillary height and visual field loss comparing referenceplane 1 and 2. II.) if there is a conformable up-down asymmetry of the peripapillary height using anew "retinal-asymmetry-difference" (RAD). III.) if conformity between peripapillary height andvisual field loss depends on the distance from the disc margin. RESULTS: 1.) For an advancedvisual field loss there was a significant correlation between visual field loss and peripapillary heightusing reference plane 1. II.) In eyes with a big up-down asymmetry of visual field loss there was abigger conformity between the up-down asymmetry of visual field loss and the up-down asymmetryof peripapillary height (11 of 12 eyes), as for a small up-down asymmetry (12 of 20 eyes). III.)Conformity decreases with the distance from the disc margin. CONCLUSIONS: Peripapillaryheight should be examined using measurement circles near the disc margin. Because of itsindependence on the age and on different reference planes additional calculation of an up-down"retinal-asymmetry-difference" (RAD) seems to be useful. Using this up-down "retinal-asymmetry-difference" (RAD) a big up-down asymmetry of visual field loss, equivalent to an advancedglaucomatous disease, is quantified with high sensitivity.

J Glaucoma 1997 Dec;6(6):363-370A comparison of healthy, ocular hypertensive, and glaucomatous optic disc topographicparameters.Iester M, Broadway DC, Mikelberg FS, Drance SM.Department of Ophthalmology, University of British Columbia, Vancouver, Canada.

PURPOSE: To compare the optic discs of 62 healthy individuals 68 patients who have ocularhypertension (OH), and 182 patients with primary open-angle glaucoma (132 high-tensionglaucoma (HTG) and 50 normal-tension glaucoma (NTG)), and determine whether disc size exertedan influence on the group differentiation. PATIENTS AND METHODS: Standard criteria wereused to define glaucoma and normality. Ocular hypertension was defined as having raisedintraocular pressure, a normal visual field, and a healthy optic disc/retinal nerve fiber layer (RNFL).The optic disc of one eye from each individual was analyzed using a confocal scanning laserophthalmoscope (Heidelberg Retina Tomograph software version 1.11, Heidelberg Engineering,Heidelberg, Germany). Thirteen topographical, volumetric, and shape parameters were comparedbetween the three diagnostic groups. In addition, the individuals were divided into subgroups on thebasis of disc size to determine any effect of disc size on the differentiating ability of the confocalscanning laser ophthalmoscope. Differences between the groups were evaluated using an analysis ofvariance. RESULTS: Glaucomatous optic discs were found to differ from both healthy and OHdiscs, although no differences in disc area between the groups were identified. On the basis of discsize, differentiating the glaucomatous discs was best for midsized discs of 2 mm2 to 3 mm2.

32

However, no difference was found between healthy and OH discs, even when allowing for disc size.CONCLUSIONS: Ocular hypertensive optic discs (with a clinically normal appearance) could notbe distinguished from healthy discs using a confocal scanning laser ophthalmoscopic technique.Glaucomatous optic discs were found to differ from both healthy and OH discs, with a limitedeffect of disc size.

Invest Ophthalmol Vis Sci 1997 Nov;38(12):2452-2459Correlation of blue-on-yellow visual fields with scanning confocal laser optic discmeasurements.Teesalu P, Vihanninjoki K, Airaksinen PJ, Tuulonen A, Laara E.Department of Ophthalmology, University of Oulu, Finland.

PURPOSE: Visual field defects and changes in the optic nerve head are signs of glaucoma. It hasbeen shown that blue-on-yellow (B-Y) perimetry can reveal visual field defects earlier and showsthem larger than does white-on-white (W-W) perimetry. The Heidelberg retina tomograph (HRT)can produce three-dimensional images of the optic disc. The aim of this study was to find out howB-Y perimetry results correlate with optic disc parameters in comparison with W-W perimetryresults. METHODS: One randomly chosen eye was evaluated in each of 40 normal subjects and 37patients with ocular hypertension and different stages of glaucoma. B-Y and W-W visual fields(program 30-2) were obtained with a Humphrey perimeter. B-Y perimetry results were adjusted forthe patient's age and lens transmission index measured with a lens fluorometer. The B-Y visual fieldadjusted mean deviation (MD) was calculated as the difference between the measured and expectedmean sensitivity values, predicted by the regression model fitted in normal subjects. The HRT withsoftware version 1.11 was used to acquire and evaluate topographic measurements of the optic disc.RESULTS: The cup shape measure showed strongest correlation with the MD of both the B-Y andW-W visual fields. The multiple correlation coefficients from quadratic regression were 0.65 forboth visual fields. Except for peripapillary retinal nerve fiber layer measurements, the statisticallysignificant correlations of the B-Y visual field indexes with other HRT parameters were equal to orbetter than those of W-W perimetry. CONCLUSIONS: B-Y perimetry MDs are well correlated withoptic nerve head parameters measured with the HRT. In early stages of glaucoma, most HRTvariables were better correlated with the B-Y MD than with the W-W MD.

Invest Ophthalmol Vis Sci 1997 Nov;38(12):2452-2459Correlation of blue-on-yellow visual fields with scanning confocal laser optic discmeasurements.Teesalu P, Vihanninjoki K, Airaksinen PJ, Tuulonen A, Laara E.Department of Ophthalmology, University of Oulu, Finland.

PURPOSE: Visual field defects and changes in the optic nerve head are signs of glaucoma. It hasbeen shown that blue-on-yellow (B-Y) perimetry can reveal visual field defects earlier and showsthem larger than does white-on-white (W-W) perimetry. The Heidelberg retina tomograph (HRT)can produce three-dimensional images of the optic disc. The aim of this study was to find out howB-Y perimetry results correlate with optic disc parameters in comparison with W-W perimetryresults. METHODS: One randomlychosen eye was evaluated in each of 40 normal subjects and 37patients with ocular hypertension and different stages of glaucoma. B-Y and W-W visual fields(program 30-2) were obtained with a Humphrey perimeter. B-Y perimetry results were adjusted forthe patient's age and lens transmission index measured with a lens fluorometer. The B-Y visual fieldadjusted mean deviation (MD) was calculated as the difference between the measured and expectedmean sensitivity values, predicted by the regression model fitted in normal subjects. The HRT withsoftware version 1.11 was used to acquire and evaluate topographic measurements of the optic disc.

33

RESULTS: The cup shape measure showed strongest correlation with the MD of both the B-Y andW-W visual fields. The multiple correlation coefficients from quadratic regression were 0.65 forboth visual fields. Except for peripapillary retinal nerve fiber layer measurements, the statisticallysignificant correlations of the B-Y visual field indexes with other HRT parameters were equal to orbetter than those of W-W perimetry. CONCLUSIONS: B-Y perimetry MDs are well correlated withoptic nerve head parameters measured with the HRT. In early stages of glaucoma, most HRTvariables were better correlated with the B-Y MD than with the W-W MD.

Ophthalmology 1997 Nov;104(11):1926-1933The associations of optic disc hemorrhage with retinal nerve fiber layer defect andperipapillary atrophy in normal-tension glaucoma.Sugiyama K, Tomita G, Kitazawa Y, Onda E, Shinohara H, Park KH.Department of Ophthalmology, Gifu University School of Medicine, Japan.

OBJECTIVE: The purpose of the study is to elucidate a topographic correlation between optic dischemorrhages and retinal nerve fiber layer defects as well as peripapillary atrophy in normal-tensionglaucoma (NTG). DESIGN: The authors prospectively studied the relation between the preciselocations of disc hemorrhages and retinal nerve fiber layer defects in the first part of the study. Theauthors also compared morphometrically the peripapillary atrophy and the optic disc in eyes withdisc hemorrhage with eyes without a history of disc hemorrhage in age-matched patients in thesecond part of the study. PARTICIPANTS: In part 1, 42 patients with NTG (male/female = 11/31;age, 56.8 +/- 14.2 years) in whom new disc hemorrhages developed were enrolled. In part 2, 51randomly selected age-matched patients with NTG without a history of disc hemorrhage(male/female = 16/35; age, 55.7 +/- 12.5) were examined. MAIN OUTCOME MEASURE: In part1, retinal nerve fiber layer defects were observed by scanning laser ophthalmoscopy using an argon-blue laser. In part 2, the area, angular extent, and radial extent of zone beta of peripapillary atrophyand the structural parameters of optic disc were measured by scanning laser tomography using adiode laser. RESULTS: In part 1, the authors detected 64 disc hemorrhages in 48 eyes of 42patients; retinal nerve fiber layer defects were shown in 47 (97.9%) of 48 eyes by scanning laserophthalmoscopy. Of 64 disc hemorrhages, 51 (79.7%) coincided with retinal nerve fiber layerdefects in location. These 51 hemorrhages were present on the border (41.2%) or adjacent to theborder (58.8%) between the retinal nerve fiber layer defect and the apparently healthy-lookingretinal nerve fiber layer. In part 2, the prevalence, area, angular extent of zone beta, and ratio ofzone beta area to disc area were significantly greater in the disc hemorrhage group than in thenonhemorrhage group, even though there were no significant differences in disc parametersbetween the two groups. CONCLUSIONS: Disc hemorrhage is associated closely with retinal nervefiber layer defect in location and the size of peripapillary atrophy in NTG.

Klin Monatsbl Augenheilkd 1997 Oct;211(4):235-240Are there genuine and pseudo-normal pressure glaucomas? Body position-dependentintraocular pressure values in normal pressure glaucoma.Mardin CY, Jonas J, Michelson G, Junemann A.Universitats-Augenklinik mit Poliklinik Erlangen-Nurnberg, Erlangen.

BACKGROUND: Elevation of intraocular pressure in the supine position has been previouslydescribed in literature. Aim of this study is to investigate the elevation of intraocular pressure innormal tension glaucoma and its effect on the morphology of the optic disc, visual field functionand capillary blood flow of the retina and optic disc. PATIENTS AND METHODS: 56 eyes of 28preperimetric and advanced normal tension glaucoma patients were prospectively evaluated. Teneyes of ten normal patients served as a control group for the measurements of the intraocular

34

pressure. In the course of a 24-h pressure profile applanation tonometry was performed in themorning in a supine and three and ten minutes later in a sitting position with Draeger's andGoldmann's tonometers. Arterial blood pressure was measured at the same time. The optic disc'smorphology was evaluated by stereo photographs and Laser Scanning Tomography. As a sensorytest computer perimetry was used. Capillary blood flow was measured at defined areas of the retinaand optic disc. An intraocular pressure above 21 mm Hg in the supine position was used as acriterium to define two groups of normal tension glaucoma patients. RESULTS: In the supineposition a statistically significant elevation of intraocular pressure was observed in 24 normaltension glaucoma patients by 6.2 +/- 2.8 mm Hg up to 21.8 +/- 3 mm Hg. Diastolic blood pressurein the supine position (80 +/- 10.5 mm Hg) was significantly lower than in the sitting position (94+/- 11 mm Hg, p = 0.021). 12 of 28 normal tension glaucoma patients showed an intraocularpressure lower than 22 mm Hg in the supine position. In these patients a tendency towards a higherincidence for the occurrence of optic disc haemorrhages and significantly higher values for bloodflow (p < 0.0005) and volume (p < 0.005) in the retina and optic nerve head could be shown. In thisgroup of normal pressure glaucoma patients a higher incidence of migraine and vasospasticcomplaints was reported in the patients' history. CONCLUSION: In this study some normal tensionglaucoma patients showed intraocular pressures in the supine position higher than 21 mm Hg and alower diastolic arterial pressure. The higher incidence of haemorrhages and higher values for flowand volume parameters of the optic disc in normal tension glaucoma patients with an intraocularpressure lower than 22 mm Hg implicate the existence of two entities: real and pseudo normaltension glaucomas.

Br J Ophthalmol 1997 Oct;81(10):871-876Laser scanning tomography of the optic nerve head in ocular hypertension and glaucoma.Hatch WV, Flanagan JG, Etchells EE, Williams-Lyn DE, Trope GE.University of Waterloo, Toronto Hospital Glaucoma Research Unit, Ontario, Canada.

BACKGROUND: This study evaluated the ability of laser scanning tomography to distinguishbetween normal and glaucomatous optic nerve heads, and between glaucomatous subjects with andwithout field loss. METHODS: 57 subjects were classified into three diagnostic groups: subjectswith elevated intraocular pressure, normal optic nerve heads, and normal visual fields (n = 10);subjects with glaucomatous optic neuropathy and normal visual fields (n = 30); and subjects withglaucomatous optic neuropathy and repeatable visual field abnormality (n = 17). Three 10 degreesimage series were acquired on each subject using the Heidelberg retina tomograph (HRT). From the14 HRT stereometric variables, three were selected a priori for evaluation: (1) volume abovereference (neuroretinal rim volume), (2) third moment in contour (cup shape), and (3) heightvariation contour (variation in relative nerve fibre layer height at the disc margin). Data wereanalysed using analysis of covariance, with age as the covariate. RESULTS: Volume abovereference, third moment in contour, and mean height contour were significantly different betweeneach of the three diagnostic groups (p < 0.001). Height variation contour showed no significantdifference among the three diagnostic groups (p = 0.906). CONCLUSIONS: The HRT variablesmeasuring rim volume, cup shape, and mean nerve fibre layer height distinguished between (1)subjects with elevated intraocular pressures and normal nerve heads, and glaucomatous optic nerveheads, and (2) glaucomatous optic nerve heads with and without repeatable visual field abnormality.This study did not directly assess the ability of the HRT to identify patients at risk of developingglaucoma. It is hypothesised that the greatest potential benefit of laser scanning tomography will bein the documentation of change within an individual over time.

Br J Ophthalmol 1997 Oct;81(10):871-876Laser scanning tomography of the optic nerve head in ocular hypertension and glaucoma.

35

Hatch WV, Flanagan JG, Etchells EE, Williams-Lyn DE, Trope GE.University of Waterloo, Toronto Hospital Glaucoma Research Unit, Ontario, Canada.

BACKGROUND: This study evaluated the ability of laser scanning tomography to distinguishbetween normal and glaucomatous optic nerve heads, and between glaucomatous subjects with andwithout field loss. METHODS: 57 subjects were classified into three diagnostic groups: subjectswith elevated intraocular pressure, normal optic nerve heads, and normal visual fields (n = 10);subjects with glaucomatous optic neuropathy and normal visual fields (n = 30); and subjects withglaucomatous optic neuropathy and repeatable visual field abnormality (n = 17). Three 10 degreesimage series were acquired on each subject using the Heidelberg retina tomograph (HRT). From the14 HRT stereometric variables, three were selected a priori for evaluation: (1) volume abovereference (neuroretinal rim volume), (2) third moment in contour (cup shape), and (3) heightvariation contour (variation in relative nerve fibre layer height at the disc margin). Data wereanalysed using analysis of covariance, with age as the covariate. RESULTS: Volume abovereference, third moment in contour, and mean height contour were significantly different betweeneach of the three diagnostic groups (p < 0.001). Height variation contour showed no significantdifference among the three diagnostic groups (p = 0.906). CONCLUSIONS: The HRT variablesmeasuring rim volume, cup shape, and mean nerve fibre layer height distinguished between (1)subjects with elevated intraocular pressures and normal nerve heads, and glaucomatous optic nerveheads, and (2) glaucomatous optic nerve heads with and without repeatable visual field abnormality.This study did not directly assess the ability of the HRT to identify patients at risk of developingglaucoma. It is hypothesised that the greatest potential benefit of laser scanning tomography will bein the documentation of change within an individual over time.

Ophthalmologe 1997 Sep;94(9):673-677Quantitative and objective follow-up of papilledema with the Heidelberg Retina Tomograph.Gobel W, Lieb WE, Grein HJ.Universitats-Augenklinik Wurzburg.

The Heidelberg retina tomograph (HRT) is a new instrument to analyze the three-dimensionalstructure of the retina. It is based on confocal laser scanning technology. Scientific interest has sofar focused on the follow-up of glaucomatous optic nerve head damage. As parameters such as cupdepth and cup volume can be reproduced with a high degree of accuracy, this new instrument mayprove to be an excellent tool to follow up swelling of the optic disk. PATIENTS AND METHOD:A total of 21 patients suffering from optic disk swelling of various etiologies were included in apilot study. Measurements were taken at six different time points. The maximum optic diskelevation and the volume of swelling were evaluated. Visual acuity and the visual field weredetermined, and fundus photographs were taken. RESULTS: A reduction in optic disk swellingover time may be demonstrated by both morphological parameters and correlates with improvementin fundus changes. The change in the volume of swelling is greater than the change in maximumdisk elevation. The course of optic disk swelling differs between patients with anterior ischemicoptic neuropathy and those with pseudotumor cerebri. No correlation was found between ourmeasurements with the HRT and functional parameters (visual acuity and visual field).CONCLUSION: The HRT is a good tool for the follow-up of optic disk swelling, particularly opticdisk elevation due to increased intracranial pressure.

J Glaucoma 1997 Aug;6(4):221-230Quantitative estimation of retinal nerve fiber layer height in glaucoma and the relationshipwith optic nerve head topography and visual field.Eid TM, Spaeth GL, Katz LJ, Azuara-Blanco A, Agusburger J, Nicholl J.

36

William and Anna Goldberg Glaucoma Service, Wills Eye Hospital, Jefferson Medical College,Philadelphia, Pennsylvania 19107, U.S.A.

PURPOSE: The authors estimated the retinal nerve fiber layer height (RNFLH) measurements inpatients with glaucoma compared with those in age-matched healthy subjects as obtained by thelaser scanning tomography and assessed the relationship between RNFLH measurements and opticand visual field status. METHODS: Parameters of optic nerve head topography and RNFLH wereevaluated in 125 eyes of 21 healthy subjects and 104 patients with glaucoma using the HeidelbergRetina Tomograph ([HRT] Heidelberg Engineering GmbH, Heidelberg, Germany) for the entiredisc area and for the superior 70 degrees (50 degrees temporal and 20 degrees nasal to the verticalmidline) and inferior 70 degrees sectors of the optic disc. The mean deviation of the visual field, asdetermined by the Humphrey program 24-2 (Humphrey Instruments, Inc., San Leonardo, CA,U.S.A) was calculated in the entire field and in the superior and inferior Bjerrum area. RESULT:Retinal nerve fiber layer height parameters (mean RNFLH and RNFL cross-sectional area) weredecreased significantly in patients with glaucoma compared with healthy individuals. Retinal nervefiber layer height parameters was correlated strongly with rim volume, rim area, and cup/disc arearatio. Of the various topography measures, retinal nerve fiber layer (RNFL) parameters and cup/discarea ratio showed the strongest correlation with visual field mean deviation in patients withglaucoma. CONCLUSION: Retinal nerve fiber layer height measures were reduced substantially inpatients with glaucoma compared with age-matched healthy subjects. Retinal nerve fiber layerheight was correlated strongly with topographic optic disc parameters and visual field changes inpatients with glaucoma.

Arch Ophthalmol 1997 Aug;115(8):983-990Effect of cataract and pupil size on image quality with confocal scanning laserophthalmoscopy.Zangwill L, Irak I, Berry CC, Garden V, de Souza Lima M, Weinreb RN.Department of Ophthalmology, University of California-San Diego, La Jolla, USA.

OBJECTIVE: To determine the effect of pupil size and cataract on the reproducibility and imagequality obtained with confocal scanning laser ophthalmoscopy. METHODS: Three image serieswere obtained with a confocal scanning laser ophthalmoscope (Heidelberg Retina Tomograph,Heidelberg, Germany) before and after pupillary dilation in each of 39 subjects (8 normal subjects,5 glaucoma suspects, and 26 patients with glaucoma). The cataract density was measured with botha lens opacity meter and the Lens Opacities Classification System III system. The image quality ofeach image series was subjectively scored on a scale of 0 (poor) to 9 (high) by 2 independentobservers who were unaware of the cataract density and pupil size during image acquisition. Theimage quality and reproducibility were objectively evaluated using the SD of the mean topographyimage of each subject. RESULTS: The mean pupil diameter in all subjects before and after dilationwas 2.5 +/- 0.8 mm and 5.8 +/- 1.4 mm, respectively. After pupillary dilation, both the mean imagequality score and mean SD of the mean topography image improved (from 4.5 +/- 3.5 to 7.4 +/- 2.3and from 48.6 +/- 18.8 microns to 35.6 +/- 15.5 microns, respectively). The quality score of theimages that were obtained before pupillary dilation was associated with the pupil size and density ofnuclear and posterior subcapsular cataracts. The SD of the mean topography images that wereobtained before pupillary dilation increased with a decreasing pupil size (P = .003) and anincreasing density of the nuclear (P < .03), cortical (P = .02), and posterior subcapsular (P = .002)opacity. CONCLUSIONS: Although pupillary dilation improved the image quality in most subjects,the improvement was sometimes small. Those subjects with small undilated pupils and/or cataractsmay benefit most from pupillary dilation.

37

Korean J Ophthalmol 1997 Jun;11(1):7-14Circumferential profiles of peripapillary surface height with confocal scanning laserophthalmoscopy.Park HJ, Caprioli J.Ghil Medical Center, Department of Ophthalmology, Inchon, Korea.

The purpose of this study was to compare the circumferential profiles of relative peripapillaryretinal surface height (RPSH) between normal and glaucoma, with a confocal scanning laserophthalmology (CSLO), and to examine the ability of the mean height to distinguish glaucoma fromnormal. Fifty-three patients with open-angle glaucoma and forty-three normal subjects matched forage, race and refractive error were studied. To extract circumferential profiles, we developedsoftware to quantify RPSH from images obtained with a CSLO (Heidelberg Retina Tomograph(HRT), Heidelberg Engineering, Germany, Software: IR1-V1.11) outside the optic disc marginevery 50 microns. Mean heights from circumferential profiles were calculated and comparedbetween normal and glaucoma. Receiver operating characteristic (ROC) curves were used toevaluate sensitivity and specificity of the mean height to discriminate normal from glaucomasubjects. T he average (+/- SD) visual field mean deviation in the glaucoma group was -4.8 +/-3.4dB. The average height of each circumference increased from the disc margin to 250 micronsaway in both normal and glaucoma subjects. There were statistically significant differences for themean height (P < 0.001) between the two groups. The largest difference between normal andglaucoma was found in the inferior sector compared with the other sectors (p < 0.001). Thesensitivity, specificity and diagnostic precision of the mean height were 83%, 67% and 76%,respectively. The mean height from the circumferential profiles of RPSH can be used as a usefulmarker to identify early glaucoma.

Ophthalmologe 1997 May;94(5):360-363Does the fundus perimetry determined edge of the blind spot depend on the superficial formof the papilla?Meyer JH, Guhlmann M, Funk J.Universitats-Augenklinik Freiburg.

BACKGROUND: We wanted to find out whether the borders of the blind spot depend on thesurface topography of the optic disc and its surrounding area. PATIENTS AND METHODS: Wetherefore examined ten eyes with parapapillary atrophy adjacent to the temporal side of the disc.Fundus perimetry was performed under direct fundus control using a Rodenstock scanning laserophthalmoscope. We examined the horizontal meridian of the optic discs in 0.5 degree steps usingGoldmann IV-stimuli with 10 different degrees of brightness and the Goldmann stimulus 1, 0 dB(greatest luminance). Six eyes with symmetric, "normal" excavation served as controls. Optic disctopography was measured with the Heidelberg Retina Tomograph (HRT). RESULTS: Stimuli witha large luminance power (Goldmann IV, 4 dB) were seen up to 0.8 degree centrally (i.e., towardsthe optic disc center) from the temporal edge of the parapapillary atrophy, but up to 1.9 degreescentrally from the nasal optic disc border (P < 0.01). Horizontal HRT section profiles of the opticdisc consistently showed prominent nasal disc borders contrasting with a shallow excavation withinthe temporal parapapillary atrophy. In all six subjects with a normally shaped disc there was nosuch "nasotemporal asymmetry." CONCLUSIONS: The size of scotomas depends on the surfacetopography of the tested area. The prominent nasal part of the optic disc appears less "blind" thanthe shallow temporal part, probably due to more intensive light scattering by the prominent nasalpart of the disc.

Phys Med Biol 1997 May;42(5):951-966

38

The scanning laser ophthalmoscope.Sharp PF, Manivannan A.Department of Biomedical Physics and Bioengineering, University of Aberdeen, Foresterhill, UK.

The imaging of the fundus of the eye poses two major technical challenges. First, it is necessary forboth the illuminating and reflected beams to pass through the same aperture, the iris. In somecommonly used instruments this leads to the use of levels of illumination close to the maximumtolerable by a patient. Second, in order to visualize the different structures present in the variouslayers of the fundus it is necessary to perform tomographic imaging. The scanning laserophthalmoscope provides an answer to these particular problems. By scanning the fundus with anarrow laser beam most of the area of the iris is then available for the reflected light and so theintensity of the illuminating beam can be kept low, making it more acceptable for patients. The useof confocal imaging allows 3D images to be produced. In this short review the performance of theinstrument will be discussed and its application to a number of clinical problems in ophthalmologyconsidered. Finally there will be a brief description of other instrumentation currently underdevelopment.

Br J Ophthalmol 1997 May;81(5):355-359Blind spot size depends on the optic disc topography: a study using SLO controlledscotometry and the Heidelberg retina tomograph.Meyer JH, Guhlmann M, Funk J.Universitats-Augenklinik, Freiburg, Germany.

AIMS: To find out whether the size of the blind spot area, determined by static perimetry, dependson the surface topography of the optic disc and its surrounding area. METHODS: Ten eyes wereexamined; all had a parapapillary atrophy adjacent to the temporal side of the disc. Microperimetrywas performed under direct fundus control using a Rodenstock scanning laser ophthalmoscope. Thehorizontal meridian of the optic discs was examined in 0.5 degree steps using five stimulus sizes(Goldmann I to V), each with 10 different degrees of brightness. Optic disc topography wasmeasured with the Heidelberg retina tomograph (HRT). RESULTS: Stimuli with a high luminancelevel (Goldmann IV, 4 dB), presented on the horizontal meridian, were seen up to 0.75 degreecentrally (that is, towards the optic disc centre) from the temporal edge of the parapapillary atrophybut up to 1.85 degrees centrally from the nasal optic disc border (p < 0.01). Horizontal HRT sectionprofiles of the optic disc consistently showed prominent nasal disc borders contrasting with ashallow excavation within the temporal parapapillary atrophy. CONCLUSIONS: The size ofscotomas depends on the surface topography of the tested area. The prominent nasal part of theoptic disc appears less 'blind' than the shallow temporal part, probably because of more intensivelight scattering by the prominent nasal part of the disc. These considerations should also apply toother scotomas.

Curr Opin Ophthalmol 1997 Apr;8(2):50-54Methods to objectify reversibility of glaucomatous cupping.Azuara-Blanco A, Spaeth GL.Glaucoma Service, Wills Eye Hospital, Philadelphia, PA 19107, USA.

Lowering intraocular pressure in adults with glaucoma may be associated with an improvement inappearance of the optic nerve head. The stage of disease, the amount of intraocular pressurereduction, and the age of the patient probably influence the occurrence of this event. The clinicalrelevance of "reversal" has not been established with certainty. The reversibility of glaucomatouscupping can be detected by subjective and qualitative means (examination of the patient or of

39

fundus photographs) or by quantitative techniques such as photogrammetry, computerized imageanalysis, and scanning laser tomography. Clinical and experimental studies are providing newinformation about the behavior of the optic nerve head tissues in response to changes in intraocularpressure.

Curr Opin Ophthalmol 1997 Apr;8(2):38-41New definitions of glaucoma.Gupta N, Weinreb RN.Glaucoma Center, University of California San Diego, La Jolla 92093-0946, USA.

At this time, there is no comprehensive and specific definition of glaucoma. Diagnostic tests such asretinal nerve fiber layer observation, scanning laser polarimetry, and confocal scanning lasertomography may improve the diagnosis and detection of glaucoma. Also, new functional tests,including short-wave-length automated perimetry, may provide better detection of glaucoma.

Curr Opin Ophthalmol 1997 Apr;8(2):7-12Laser scanning tomography and angiography of the optic nerve head for the diagnosis andfollow-up of glaucoma.Melamed S, Levkovitch-Verbin H.Sam Rothberg Glaucoma Center, Goldschleger Eye Institute, Sheba Medical Center, Tel-Hashomer,Israel.

New imaging technologies allow us to detect and follow very subtle changes of the structure andperfusion of the optic nerve head. Two of these technologies, confocal scanning laserophthalmoscopy and confocal tomographic angiography are reviewed, focusing on new data andadvances reported in the past year. These and other technologies (eg, nerve fiber layer polarimetry,optical coherent topography, and laser doppler flowmetry) will enhance the ability to diagnose andmonitor glaucomatous disc damage.

Ophthalmology 1997 Mar;104(3):545-548The effect of optic disc size on diagnostic precision with the Heidelberg retina tomograph.Iester M, Mikelberg FS, Drance SM.Department of Ophthalmology-University of British Columbia, Vancouver, Canada.

PURPOSE: The authors evaluated the ability of a confocal scanning laser ophthalmoscope to detectglaucomatous visual field loss by using their previously described discriminant formula on aprospectively obtained cohort. The relationship of optic disc size to diagnostic classification wasalso evaluated. METHODS: One eye was chosen randomly from each of 153 subjects. Sixty controleyes had intraocular pressure less than 21 mmHg and normal visual fields; 93 glaucomatous eyeshad intraocular pressure greater than 21 mmHg and abnormal visual fields. The optic disc statuspurposely was not used for classification purposes. All subjects were examined with the HeidelbergRetina Tomograph (HRT; Heidelberg Engineering GMBH, Heidelberg, Germany) and HumphreyPerimeter, program 30-2 (Humphrey Instruments, Inc., San Leandro, CA). Visual fields wereconsidered abnormal by the authors' previously published criteria. The HRT classification used age,adjusted cup shape measure, rim volume, and height variation contour to classify the optic disc asnormal or glaucomatous. Then the authors assessed the sensitivity, specificity, and diagnosticprecision for the entire group, and for three subsets classified by disc area: disc area less than 2mm2, between 2 and 3 mm2, and more than 3 mm2. RESULTS: The entire group had a sensitivity,specificity, and diagnostic precision of 74%, 88%, and 80%, respectively. The specificity was 83%

40

when disc area was less than 2 mm2 and improved to 89% when disc area was more than 2 mm2.The sensitivity tended to improve from 65% to 79%, and to 83% if the disc area increased, but thedifference was not statistically significant. CONCLUSIONS: In a prospective cohort of patients, theHRT discriminant analysis formula was capable of detecting glaucomatous visual field loss withgood precision. Unusually small optic discs continue to present diagnostic difficulties.

Ophthalmology 1996 Nov;103(11):1899-1906Correlation between peripapillary atrophy and optic nerve damage in normal-tensionglaucoma.Park KH, Tomita G, Liou SY, Kitazawa Y.Department of Ophthalmology, College of Medicine, Seoul National University Hospital, Korea.

PURPOSE: To investigate the correlation between peripapillary atrophy and visual field defects aswell as optic nerve head configurations in patients with normal-tension glaucoma (NTG).METHODS: Topographic measurements for peripapillary atrophy and optic nerve head usingconfocal scanning laser tomography and automated static threshold perimetry were performed on102 eyes of 51 patients with NTG. Peripapillary atrophy was divided into (1) a central zone (zoneBeta) with visible, large choroidal vessels and sclera, and (2) a peripheral zone (zone Alpha) withirregular hyper- and hypopigmentation. The area, angular extent around the disc, and radial extentof each zone were measured. RESULTS: The area and extent of zone Beta increased significantlywith increasing visual field defects expressed in terms of mean deviation, corrected pattern standarddeviation, central visual field defects within 5 degrees of fixation, and superior hemifield defects (r= 0.3770-0.5291, P < 0.01). The angular extent of zone Beta represented localized field defectsbetter (r = 0.5217, P < 0.001) than diffuse field defects (r = -0.3770, P < 0.01). Zone Betasignificantly correlated with optic nerve head topography. Intraindividual right-left-side differencesof corrected pattern standard deviation showed the highest correlation with the side differences ofzone Beta area (r = 0.6305, P < 0.001). The location of visual field defects correlated significantlywith the location of peripapillary atrophy (chi-square = 9.0484, P = 0.011). Zone Alpha was notsignificantly correlated with visual field defects or optic nerve head configurations (P > 0.05).CONCLUSION: Peripapillary atrophy is significantly associated with functional and structuraloptic nerve damage in NTG.

Am J Ophthalmol 1996 Nov;122(5):690-695Change in optic disk topography after trabeculectomy.Irak I, Zangwill L, Garden V, Shakiba S, Weinreb RN.Glaucoma Center and Research Laboratories, University of California, San Diego 92093-0946,USA.

PURPOSE: To investigate the relationship between optic disk topography and intraocular pressurebefore and after trabeculectomy with confocal scanning laser ophthalmoscopy. METHODS: Theeyes of 49 consecutive patients undergoing trabeculectomy at a university-based glaucoma practiceunderwent preoperative and postoperative imaging using a confocal scanning laser ophthalmoscope(Heidelberg Retina Tomograph). Three images of one eye of each patient were obtained with a 15-degree field of view. Preoperative images were obtained approximately 2 months before surgery(mean +/- SD, 2.4 +/- 1.6 months). Postoperative images were obtained at least 3 months aftersurgery (mean, 4.5 +/- 2.6 months). RESULTS: Mean preoperative intraocular pressure,postoperative intraocular pressure, and percent change in intraocular pressure respectively were23.1 +/- 6.8 mm Hg, 12.7 +/- 7.1 mm Hg, and 43.8% +/- 29.9%. A significant association (P < .01)was found between percent decrease in intraocular pressure and decreases in cup area, cup volume,and cup/disk area ratio as well as between percent decrease in intraocular pressure and increases in

41

rim area, rim volume, mean height contour, retinal cross-section area, and height in contour.Between 11.7% and 31.2% of the variability (R2) in these parameters was explained by the percentchange in intraocular pressure. Topography changes were more strongly associated with percentchange than with mean change in intraocular pressure. We found no association between percentdecrease in intraocular pressure and reference plane height or maximum cup depth.CONCLUSIONS: Changes in optic nerve topography were associated with reduction in intraocularpressure after trabeculectomy.

42

Heidelberg Retina Tomograph und MaculaMedline Abstracts Dezember 1996 bis März 2001

Ophthalmic Surg Lasers 2001 Mar;32(2):95-99Three-dimensional analysis of macular diseases with a scanning retinal thickness analyzerand a confocal scanning laser ophthalmoscope.Konno S, Takeda M, Yanagiya N, Akiba J, Yoshida A.Department of Ophthalmology, Asahikawa Medical College, Japan. skonno@asahihawa-med.ac.jp

OBJECTIVE: To compare three-dimensional analysis of macular diseases obtained using thescanning retinal thickness analyzer (RTA) with that obtained using the confocal scanning laserophthalmoscope, Heidelberg Retina Tomograph (HRT). PATIENTS AND METHODS: Both theRTA and the HRT were used to examine 50 eyes of 36 patients with diabetic macular edema,macular edema following branch retinal vein occlusion, age-related macular degeneration, andidiopathic macular holes. RESULTS: In most macular diseases, the retinal thickness mapconstructed using the RTA agreed with the image obtained with the HRT. The two maps were notconsistent with each other, however, in patients with dense retinal hemorrhages and withextrafoveal fixation. CONCLUSIONS: Although both the RTA and the HRT give additionalinformation to clinically evaluate macular diseases, they do have limitations. The discrepancybetween these two analyses in some specific macular pathologies might be caused by the differentwavelengths of the laser beam and the different methodologies used to scan the retina.

Br J Ophthalmol 2001 Jan;85(1):34-39Sensitivity and specificity of a new scoring system for diabetic macular oedema detectionusing a confocal laser imaging system.Tong L, Ang A, Vernon SA, Zambarakji HJ, Bhan A, Sung V, Page S.Department of Ophthalmology, Queen's Medical Centre, University Hospital, Nottingham NG7

AIM: To assess the use of the Heidelberg retina tomograph (HRT) in screening for sight threateningdiabetic macular oedema in a hospital diabetic clinic, using a new subjective analysis system(SCORE). METHODS: 200 eyes of 100 consecutive diabetic patients attending a diabetologist'sclinic were studied, all eyes had an acuity of 6/9 or better. All patients underwent clinicalexamination by an ophthalmologist. Using the HRT, one good scan was obtained for each eyecentred on the fovea. A System for Classification and Ordering of Retinal Edema (SCORE) wasdeveloped using subjective assessment of the colour map and the reflectivity image. Theinterobserver agreement of using this method to detect macular oedema was assessed by twoobservers (ophthalmic trainees) who were familiarized with SCORE by studying standard picturesof eyes not in the study. All scans were graded from 0-6 and test positive cases were defined ashaving a SCORE value of 0-2. The sensitivity of SCORE was assessed by pooling the data with anadditional 88 scans of 88 eyes in order to reduce the confidence interval of the index. RESULTS: 12eyes in eight out of the 100 patients had macular oedema clinically. Three scans in three patientscould not be analysed because of poor scan quality. In the additional group of scans 76 out of 88eyes had macular oedema clinically. The scoring system had a specificity of 99% (95% CI 96-100)and sensitivity of 67% (95% CI 57-76). The predictive value of a negative test was 87% (95% CI82-99), and that of a positive test was 95% (95% CI 86-99). The mean difference of the SCOREvalue between two observers was -0.2 (95% CI -0.5 to +0.07). CONCLUSIONS: These datasuggest that SCORE is potentially useful for detecting diabetic macular oedema in hospital diabeticpatients.

43

Nippon Ganka Gakkai Zasshi 2000 Dec;104(12):899-942New examination methods for macular disorders--application of diagnosis and treatment.Yoshida A.Department of Ophthalmology, Asahikawa Medical College.

To establish a diagnosis or evaluate the efficacy of treatment for macular disorders, we needmethods to evaluate the anatomical and functional changes of these disorders. In this article, wedescribe several studies that we have conducted for 2 years. In section 1, we report our newmethods for making a diagnosis and evaluating visual function in macular disorders. In section 2,we describe our trials of these examination methods in treatment. Here is the summary of ourresults. In section 1, to examine the structures of the macular area, we used a retinal thicknessanalyzer (RTA), a confocal scanning laser ophthalmoscope (Heidelberg Retina Tomograph, HRT),and optical coherence tomography (OCT) to measure retinal thickness and assess retinalmicrostructures. We compared retinal imaging analysis of various macular diseases obtained withthese three instruments. With the RTA, we obtained good three-dimensional macular imagesdisplayed on a retinal thickness map, but the retinal thickness map did not demonstrate thethickened retina with dense retinal hemorrhages, and high backscattering from hard exudates mightobscure the vitreoretinal interface. The HRT three-dimensional topographic image clearly showedthe undulation of the retinal surface. However, it took a relatively long time to obtain the HRTimage, and we sometimes could not obtain good topographic images because of fixation movement.Examination with the OCT allows confirmation of the retinal cross-sectional structures, such asretinoschisis or cystoid spaces and the vitreomacular interface, such as vitreous traction, that cannotbe detected using other conventional methods with high resolution, but high reflectivity from densehemorrhages obscured the deeper layers of the retinal structures. Measurement of retinal thicknessobtained with both the RTA and OCT is highly reproducible, and there was significant correlationbetween the retinal thicknesses measured with the two instruments. We believe that these threeinstruments might contribute significantly to early, accurate diagnosis and better monitoring of thetherapeutic effects of vitrectomy for macular diseases. In the future, if these fundus imaginganalysis instruments can achieve higher resolution and can analyze three-dimensional retinalimages, they will provide better information to clinically evaluate macular diseases. Wedemonstrated vitreous examination and examination from the retinal surface to the deeper retinallayer at the macular area using a scanning laser ophthalmoscope (SLO). The SLO examination withan argon laser and a large confocal aperture was useful for conducting kinetic examination of thevitreous opacity above the macula. With a diode laser and a ring aperture (dark-field mode), it waspossible to examine the retina from the deeper retinal layer to the choroids. On the other hand, theSLO also allows us to conduct a functional examination of fixation. We demonstrated that thereferred retinal locus of fixation may change during the follow-up period in patients whose centralfixation is impaired due to macular disease, and we showed that the fixation behavior was related tothe visual acuity. Therefore, the SLO is an ideal instrument for determining the visual field and thevisual acuity before and after treatment in patients with macular disease, because of its preciselocalization of the examination point by directly observing the fundus and by monitoring fixationbehavior. Our new program installed in the SLO allows us to complete the quantitative retinalsensitivity evaluation within 2 minutes, which is difficult to do using a conventional SLO program.Furthermore, we demonstrated for the first time that minute functional changes in the retina can bedetected by the SLO under low background illuminance. Such changes cannot be detected underconventional conditions. In addition, the extrafoveal visual acuity of normal subjects and patientswith macular disease was studied using this new SLO program. The iso-acuity lines could beillustrated by summarizing these results in normal subjects. The SLO acuity of the horizontalmeridian is significantly better than that of the vertical meridian, and even in the nasal area adjacentto the optic disc, an acuity of better than 0.1 could be achieved. To evaluate macular function, wealso investigated the blood flow of the choroid (CF), the retina (RF), and the choriocapillaris at the

44

fovea (CCF). We investigated the CF in patients with age-related macular degeneration (AMD)using pulsatile ocular blood flow (POBF) measurements. In patients with exudative AMD, thePOBF was significantly lower than in patients with nonexudative AMD or in control subjects.Decreased CF may play a role in the development of choroidal neovascularization in AMD. RF wasmeasured using laser Doppler velocimetry (LDV).

Br J Ophthalmol 2000 Oct;84(10):1194-1197Improvement of reproducibility of macular volume measurements using the Heidelbergretinal tomograph.Ang A, Tong L, Vernon SA.Department of Ophthalmology, Queen's Medical Centre, University Hospital, Nottingham NG72UH, UK.

AIMS: To develop a more reproducible method of macular volumetric analysis in order to facilitateserial monitoring of changes in retinal oedema with time. METHODS: The Heidelberg retinaltomography (HRT) machine was used to scan the macula of 20 normal subjects and 40 diabeticswith macular oedema. The volume above reference plane (VARP) within a 2 mm diameter and 3mm diameter circle was measured twice in each eye. The position of the circle to be measured wascarefully defined relative to major retinal vessels. As a modification to the previously publishedtechnique, fluctuation of the height of the contour line relative to the focal plane of the eye iscompensated for by an adjustment of the reference plane. The position of the circle was controlledrelative to major retinal vessels using an acetate. The reproducibility of VARP measurement wasassessed by three variables-the standard error of the difference on two isolated VARPmeasurements, the standard error of the difference between the average of three readings on twodifferent occasions, as well as the coefficient of variation (COV). RESULTS: Both the 2 mm and 3mm circles showed good reproducibility in VARP measurements. In normal subjects, the COV ofVARP for 2 mm circles and 3 mm circles were 13% and 12% respectively. In patients with macularoedema, the COV of VARP for 2 mm circles and 3 mm circles were 9% and 11% respectively.CONCLUSION: The modification of VARP measurements between scans of the same eye hasimproved the COV from 31% to 9% in eyes with diabetic macular oedema.

Am J Ophthalmol 2000 Jul;130(1):65-75Three-dimensional observations of developing macular holes.Kishi S, Takahashi H.Department of Ophthalmology, Gunma University School of Medicine, Maebashi, Gunma, Japan.kishi@med.gunma-u.ac.jp

PURPOSE: To describe the morphologic features of idiopathic macular holes and vitreous tractionduring macular hole evolution. METHODS: We prospectively examined 89 eyes of 82 patients withidiopathic macular holes (stage 1, 15 eyes; stage 2, 16 eyes; stage 3, 50 eyes; stage 4, eight eyes)using optical coherence tomography. In addition to optical coherence tomography, scanning laserophthalmoscopy was performed in all 15 eyes with stage 1 hole, six of 16 eyes with stage 2, and 19of 50 eyes with stage 3. RESULTS: In stage 1 eyes, optical coherence tomography revealed retinalsplit or cystic changes at the fovea in 11 of 15 eyes (73%) and foveal retinal detachment in foureyes (27%). Two eyes with foveal cysts progressed to stage 2, and one developed a stage 3 hole. Inone eye with retinal detachment, the detached retina thinned and developed dehiscence. Opticalcoherence tomography showed a vitreous cortex that was detached in the perifoveal area butattached on the fovea in 11 of the 15 stage 1 eyes. In stage 2 macular holes, retinal tissue extendingfrom the perifoveal retina formed a flap. Scanning laser ophthalmoscopy demonstrated intraretinalradiating striae, which corresponded to a foveal cyst or perifoveal cystic changes. CONCLUSIONS:

45

Macular holes start as retinal splits or foveal cysts in most cases. The anterior wall of the cyst servesas a flap in stage 2 and an operculum in stage 3 holes. Radiating striae correspond to retinal splits orcysts and presumably represent an elevation of Henle fiber. In a few macular holes, fovealdetachment is the initial change. The detached retina thins and eventually develops a hole. In bothcourses, anterior traction of the slightly detached vitreous cortex appears to be a major contributingfactor to macular hole formation.

Graefes Arch Clin Exp Ophthalmol 2000 May;238(5):410-419Quantitative measurements of changes of idiopathic stage 3 macular holes after vitrectomyusing confocal scanning laser tomography.Kobayashi H, Kobayashi K.Department of Ophthalmology, Amagasaki Hospital, Amagasaki, Japan.kobihkkk@mediawars.ne.jp

PURPOSE: To perform quantitative three-dimensional analysis of changes of idiopathic full-thickness stage 3 macular holes following vitrectomy and gas tamponade using confocal scanninglaser tomography to study the mechanism of repairing the holes and to correlate with visualrecovery. METHODS: We studied 44 patients, 10 men and 34 women, aged between 40 and 76years (mean 65.5 years) with stage 3 macular holes with symptoms of 1-4 months' duration (mean2.7 months). Using the Heidelberg Retina Tomograph, we measured the macular area within 1 weekbefore surgery (3.5+/-1.6 days), and between 2 and 4 weeks (2.4+/-0.6 weeks) and at least 3 months(3.8+/-00.8 months) after surgery. RESULTS: All 44 eyes showed closure of the holes andflattening of cuff and retinal striae after vitrectomy and gas tamponade. All the eyes showed smallflat depressions that corresponded to each macular hole with the area of 0.027-0.184 mm2 (0.110+/-0.042 mm2). Thirty-nine (89%) of 44 eyes showed large concave depressions that appearedto correspond to the preoperative retinal striae, with areas of 0.844 to 5.563 mm2 (3.688+/-1.263mm2). The areas of the postoperative small depressions and large depressions were significantlycorrelated with the area, volume, and depth of the macular holes and the area of the cuff and retinalstriae prior to treatment. Postoperative visual acuity showed significant correlations with the areasof the postoperative small depressions and large depressions. CONCLUSIONS: Confocal scanninglaser tomography is potentially useful as a noninvasive diagnostic technique for quantitativemeasurements of changes of macular holes by vitrectomy and gas tamponade. Postoperative smalldepressions corresponding to the healed macular holes appeared to be caused by gliosis involvingsealing of the holes. The large depressions and their concave shape may result from postoperativechanges of the retina, including swelling of ganglion cells and loss of outer and inner segments ofphotoreceptor cells in regions of preoperative cuff and retinal striae.

Ophthalmology 2000 Mar;107(3):593-599Comparison between optical coherence tomography and fundus fluorescein angiography forthe detection of cystoid macular edema in patients with uveitis.Antcliff RJ, Stanford MR, Chauhan DS, Graham EM, Spalton DJ, Shilling JS, Ffytche TJ, MarshallJ.GKT Department of Ophthalmology, Rayne Institute, St Thomas' Hospital, London, England.

PURPOSE: To compare optical coherence tomography (OCT) with fundus fluorescein angiography(FFA) for the detection of cystoid macular edema (CME) in patients with uveitis. DESIGN:Prospective comparative observational series. PARTICIPANTS: One hundred twenty-one eyes of58 patients with uveitis of varied causes (seven patients were studied twice). TESTING: Patientswith suspected CME underwent OCT scanning followed by FFA at the same visit. MAINOUTCOME MEASURES: Detection and distribution of macular edema. RESULTS: One hundred

46

eight eyes had similar results on both OCT and FFA in that 67 eyes had CME and 41 eyes had noCME. In 10 eyes subretinal fluid was detected on OCT but not FFA. Five of these eyes had CMEon FFA but not OCT. Three other eyes had CME that was detected by FFA but not by OCT.Compared with FFA, the OCT sensitivity for detecting CME was 96% (including the eyes withsubretinal fluid), and the OCT specificity was 100%. CONCLUSIONS: OCT is as effective atdetecting CME as is FFA but is superior in demonstrating axial distribution of fluid.

Ophthalmologe 2000 Mar;97(3):173-180Volume determination of pigment epithelium detachment in AMD by laser scanningtomography.Spital G, Brumm G, Radermacher M, Muller C, Lommatzsch A, Pauleikhoff D.Augenabteilung, St. Franziskus Hospital, Munster.

BACKGROUND: The possibility of using 3D mapping of AMD-related RPE detachments bymeans of laser scanning tomography was evaluated to correlate the fluorescein and tomographicfindings. METHODS: Sixty eyes with AMD-related RPE detachments of 55 consecutive patients(19 men, 36 women) between 54 and 87 years of age (mean: 72.2 years) were examined using theHeidelberg Retina Tomograph (HRT). The parameters considered were area, volume, maximalheight and 3D configuration of the RPE detachments. The tomographic data were analyzed andcorrelated with the fluorescein angiographic findings. Follow-up examinations were done at 3 and 6months later. RESULTS: The mean +/- SD area of elevation was 10.59 +/- 5.51 mm2 (range, 0.93-19.73), which correlated well with the angiographic measurements. The mean maximal height was0.42 +/- 0.19 mm (range, 0.11-0.83), mean volume was 2.55 +/- 1.9 mm3 (range, 0.073-6.63). Wefound a tendency to grow for untreated RPE detachments, depending on the volume at the firstmeasurement. Three RPE detachments of high volume (mean 0.501 +/- 1.3 mm3) resulted in tearingof the RPE. The angiographic findings of localized neovascularizations in the RPE detachment area(39 of 60 eyes) showed a corresponding irregularity of the surface in most of the correlating 3DHRT figures. CONCLUSIONS: Confocal laser scanning tomography allows analysis of 3Dconfigurations and a quantitative measurement of RPE detachments in AMD. Therefore, thisdiagnostic technique appears to be useful, especially for differentiated follow-up examinations (asin therapy-control studies). Furthermore, the analysis of 3D configurations seems to be useful toestimate the risk of tearing of the RPE and may help to indicate underlying neovascularizations.

Ophthalmic Surg Lasers 1999 Jul;30(7):513-517Three-dimensional characteristics of macular pseudoholes using confocal laser tomography.Akiba J, Yanagiya N, Konno S, Hikichi T, Yoshida A.Department of Ophthalmology, Asahikawa Medical College, Japan. jakiba@asahikawa-med.ac.jp

BACKGROUND: Epiretinal membranes with macular pseudoholes are sometimes confused withfull-thickness macular holes. Because both the natural course and clinical management of the twodiffer, an accurate differential diagnosis is needed. PATIENTS AND METHODS: We obtainedthree-dimensional images of macular pseudoholes in 12 eyes using the Heidelberg retina tomograph(HRT). Another 15 eyes with a full-thickness macular hole were also studied. In addition, wemeasured the area and the maximum depth of both types of holes. RESULTS: Irregular ripplingundulations were frequently observed on the three-dimensional topographic maps around thepseudoholes, whereas elevated cuffs were observed around the full-thickness holes. The maximumdepth of the macular pseudoholes (mean, 57 microm) was significantly shallower than that of thefull-thickness macular holes (mean, 156 microm; P < 0.01). CONCLUSION: Three-dimensionalimages obtained by the HRT and the measurement of the maximum depth may be useful indifferentiating macular pseudoholes from full-thickness macular holes.

47

Graefes Arch Clin Exp Ophthalmol 1999 Apr;237(4):283-288Correlation of quantitative three-dimensional measurements of macular hole size with visualacuity after vitrectomy.Kobayashi H, Kobayashi K.Department of Ophthalmology, Amagasaki Hospital, Hyogo, Japan. kobihkkk@mediawars.or.jp

OBJECTIVE: The purpose of the study was to study the relationship of postoperative visualoutcome with anatomical parameters of macular holes using confocal scanning laser tomographyand to predict the postoperative visual results. DESIGN: Cohort study. INTERVENTION ANDPARTICIPANTS: We evaluated the eyes of 44 patients undergoing macular hole surgery (10 menand 34 women aged 40-76 years, mean 59.1 years). All patients showed idiopathic full-thicknessstage 3 macular holes. The duration of symptoms was 1-4 months (mean 2.7 months). MAINOUTCOME MEASURES: The area, volume, mean depth, and maximum depth of the macularholes and the areas of cuff and retinal striae were measured using the Heidelberg Retina Tomographpreoperatively. RESULTS: All 44 eyes showed closure of the holes and flattening of cuff andretinal striae after vitrectomy and gas tamponade. Postoperative visual acuity was significantlycorrelated with the area (r = 0.822, P<0.0001), volume (r = 0.840, P<0.0001), mean depth (r =0.842, P<0.0001), and maximum depth (r = 0.831, P<0.0001) of the macular holes, area of cuff (r =0.625, P<0.0001), and area of retinal striae (r = 0.648, P<0.0001). Multiple regression analysisshowed that the combination of the preoperative mean depth of macular holes and logarithm ofpreoperative visual acuity was the strongest predictor of the postoperative visual acuity.CONCLUSIONS: Postoperative visual results vary significantly with the size of macular holes inpatients with stage 3 macular holes of duration 1-4 months. The use of the confocal scanning lasertomography may facilitate the evaluation of macular holes efore surgery. Ability to predict thepostoperative visual results would be helpful in treating patients with macular holes.

Doc Ophthalmol 1999;97(3-4):349-360Reproducibility of volumetric macular measurements in diabetic patients with the HeidelbergRetina Tomograph.Zambarakji HJ, Vernon SA, Spencer AF, Amoaku WM.Department of Ophthalmology, Queen's Medical Centre, University Hospital, Nottingham, UK.

AIMS: To quantify diabetic macular edema by confocal scanning laser ophthalmoscopy and assessits usefulness by determining the reproducibility of topographic measurements at the macula.METHODS: The volumes above reference plane bound by a 2 mm diameter circle centred on thefovea were measured by two observers. The reference plane was adjusted to the lowest point of theheight variation of the contour line. The reproducibility of this technique was assessed in 20 eyes of20 diabetic patients of which 8 eyes had macular edema. Three HRT scans of each eye wereobtained. The measurements of volume above reference plane of each scan were repeated threetimes. RESULTS: For all diabetic eyes, the intra scan coefficients of variability measured 14.71%to 21.21%, the inter scan coefficient of variability was 30.46%. The average standard deviationswere 0.053 mm3 for one examination per scan, 0.047 mm3 for two examinations per scan and 0.044mm3 for three examinations per scan. Linear regression demonstrated an increase in standarddeviation with greater volumetric measurements (p < 0.001). We found good correlation (r = 0.959,p < 0.001) and strong agreement between the two observer's findings for all 20 eyes. For the 8 eyeswith macular edema, the coefficients of variability were similar to those calculated for all 20 eyes.The average SD for one examination per scan were 0.078 mm3, 0.069 mm3 for two examinationsper scan and 0.062 mm3 for three examinations per scan. We found good correlation (r = 0.945, p <0.001) and strong agreement between the two observer's findings in eyes with edema.

48

CONCLUSION: The reproducibility of this technique has been demonstrated in diabetic eyes. Thismay have useful clinical applications for the quantification of diabetic macular edema andmonitoring of laser therapy.

Ophthalmology 1999 Feb;106(2):274-279The use of confocal scanning laser tomography in the evaluation of retinal elevation in age-related macular degeneration.Jaakkola A, Vesti E, Immonen I.Department of Ophthalmology, Helsinki University Central Hospital, Finland.

OBJECTIVE: To evaluate the feasibility of using confocal scanning laser tomography in theanalysis of macular topography in patients with subfoveal choroidal neovascularization associatedwith age-related macular degeneration (AMD) and to analyze quantitatively the changes intopography after local strontium-plaque radiation therapy. DESIGN: Prospective case series.PARTICIPANTS: A total of 16 eyes with subfoveal choroidal neovascular membranes (CNVM)treated with strontium-90 (90Sr)-plaque radiation therapy and 16 fellow eyes of 16 patients wereexamined. INTERVENTION: Confocal scanning laser analysis of macular surface topographybefore and after irradiation of the macula was performed. MAIN OUTCOME MEASURES:Parameters describing the height and volume of the retinal elevation in the macula were measured.RESULTS: The maximum height of the macular lesion at baseline was 0.25 mm (standarddeviation [SD], 0.12 mm) in eyes showing regression of the CNVM during follow-up and 0.34 mm(SD, 0.19 mm) in eyes showing continued growth of the CNVM. During follow-up, a meandecrease in the maximum height of the macular lesion ranging from 0.03 to 0.10 mm occurred ineyes with regression of the CNVM, whereas the mean maximum height increased by 0.07 to 0.15mm during follow-up visits in eyes with continued growth of the CNVM. All parameters describingthe mean height and volume of the lesion also decreased significantly in patients showingangiographic regression, whereas they increased or remained unchanged in patients with continuousgrowth of the CNVM despite irradiation. The corresponding parameters also were higher in felloweyes with untreated CNVM than in eyes without exudative AMD. CONCLUSIONS: Confocalscanning laser tomography can be used to monitor the amount of the change in neurosensorydetachment in AMD. The parameters obtained by confocal scanning laser tomography correlatewith CNVM perfusion after 90Sr-plaque radiation therapy. This technology is a useful tool forobjective evaluation of morphologic change after institution of new therapeutic methods for thetreatment of AMD.

Br J Ophthalmol 1997 Feb;81(2):107-116Objective morphological assessment of macular hole surgery by scanning laser tomography.Hudson C, Charles SJ, Flanagan JG, Brahma AK, Turner GS, McLeod D.University Department of Ophthalmology, Manchester Royal Eye Hospital.

AIM: To assess the morphological change in retinal topography using a scanning laser tomographerfollowing macular hole surgery. To compare the results of scanning laser tomography with clinicalevaluation and visual function assessment. METHODS: The sample for this pilot study comprisedfour eyes exhibiting different stages of macular hole formation preoperatively. Subjects wereassessed preoperatively and at 1 and 3 months postoperatively. Each assessment included visualacuity, letter contrast sensitivity, clinical examination (including automated static perimetry), andscanning laser tomography. The Heidelberg retina tomograph (HRT) was used to acquire digitisedscanning laser tomography images of the macula (10 degrees and 20 degrees fields). Surgeryessentially comprised vitrectomy, peeling of the posterior hyaloid face, if still attached, andintraocular gas tamponade. The magnitude and significance of topographic change were determined

49

postoperatively using the HRT topographic difference facility. RESULTS: Topographic differenceanalysis of the right and left eyes of case 1 showed a significant reduction in the height of the retinapostoperatively. Topographic difference analysis of case 2 showed no significant change intopography. Topographic difference analysis of case 3 showed a significant increase in the height ofthe retina postoperatively. Scanning laser tomography agreed with clinical assessment based uponfundus biomicroscopy in three of the four eyes studied; the postoperative closure of the stage 2macular hole (as noted by clinical assessment) proved to be too small to reach statisticalsignificance. Scanning laser tomography agreed with the assessment of visual function in two eyes;the agreement between scanning laser tomography and visual function depends, in part, on the stageof development of the macular hole. CONCLUSION: Scanning laser tomography provides anobjective evaluation of the outcome of macular hole surgery. Studies employing larger sample sizesare required to fully determine the clinical worth of the technique.

Am J Ophthalmol 1996 Dec;122(6):864-869Three-dimensional measurements of central serous chorioretinopathy using a scanning lasertomograph.Weinberger D, Stiebel H, Gaton DD, Friedland S, Priel E, Yassur Y.Department of Ophthalmology, Rabin Medical Center, Petah Tiqva, Israel.

PURPOSE: To evaluate the topographic three-dimensional mapping of retinal elevation in centralserous chorioretinopathy using the Heidelberg Retina Tomograph and to correlate the measuredparameters with the fluorescein angiographic findings. METHODS: Seventy-six consecutivepatients with central serous chorioretinopathy (63 men, 13 women), between 26 and 54 years ofage, were examined to identify areas of neurosensory retinal detachment and fluorescein leakage. Inareas of retinal detachment, the parameters measured were the area, volume, maximal height, anddiameters of the retinal elevation, which were statistically analyzed, and the correlations betweenthese parameters were evaluated. RESULTS: Mean +/- SD area of elevation was 9.6 +/- 5.22 mm2(range, 2.7 to 21.5 mm2); mean volume was 1.16 +/- 1.3 mm3 (range, 0.11 to 4.73 mm3); meanmaximal height was 238 +/- 108 microns (range, 97 to 450 microns); mean x-axis was 3.4 +/- 1.1mm (range, 1.6 to 5.6 mm); and mean y-axis was 3.03 +/- 0.98 mm (range, 1.6 to 4.7 mm). Most ofthe retinal elevations were oval (the x-axis longer than the y-axis); the maximal height was in thegeometric center in the smaller blebs and below the geometric center in the larger blebs. There werestatistically significant correlations between area, volume, and height of the sensory elevation. Nocorrelation was found between the location and the shape of leakage on fluorescein angiographyand the Heidelberg Retina Tomograph measurements. CONCLUSIONS: Confocal lasertomography is potentially useful as a noninvasive diagnostic technique for quantitativemeasurements of the neurosensory retinal detachment in central serous chorioretinopathy.