Evaluation & Surgical Correction of Astigmatism Jean Luc Febbraro MD Rothschild Foundation Paris...

Evaluation & Surgical Correction of Astigmatism

Jean Luc Febbraro MDRothschild Foundation

Paris France

[email protected]@febbraro.net

Evaluation & Surgical Correction of Astigmatism

Financial disclosureAlcon Laboratories: C, Croma: C

Bausch & Lomb Surgical: C,L

Surgical Correction of Astigmatism

Evaluation & Principles

Prevalence & EvolutionPrevalence & Evolution

Cataract incisions SIA Cataract incisions SIA

Evaluation of Astigmatism

• K-readings– 2mm central

• Topography– Placido, Scheimflug (cornea > 2mm)– Aberrometers (cornea, internal)

• Refraction– Total astigmatism (subjective, objective)


Topography (placido) Precise measurement

Magnitude, axis Symmetry Regularity Detection

K. fruste Pellucid Deg.


Aberrometers (Hartman-Shack, OPD)

Precise measurement Lower order ab. (Sph, cyl.) Higher order ab. (coma,

trefoil, sph. aberrations) Distinction

Total, internal


• Refraction (Subjective, objective)

– Perfect match required• Subjective

– (Sph, cyl)• Objective

– (Sph, cyl & HOA)• Enable WF ablation

Astigmatic Correction & Cataract Patients

Surgical options: • Incisional techniques

• LRI, AK• Toric IOLs• Laser vision correction

• PRK, LASIK

Astigmatic Correction & Incisional Techniques

Principles: • The cornea flattens over an incision

• Transverse incisions increase the radius of curvature in one meridian only

• The flattening effect increases as incisions approach the visual axis


Coupling: The flattening effect of a transverse incision is

associated with a steepening effect 90° away.

• Coupling ratio tend to be one to one.

• The spherical equivalent remains unchanged.


Principles: Incisions are always placed on the steep

meridian.

• The longer and deeper the incision the greater the effect.

• The older the patient the greater the effect.

Astigmatic Correction with LRI

LRI / PRI Placed on the steepest meridian Located at the limbus (9.0-11.0-mm OZ)

4242

4444

Astigmatic Correction with LRI

Principles Flatten the steepest meridian Steepen the axis at 90° Coupling ratio 1:1

4444

42424343

4343

Astigmatic Correction: LRI / AK

LRI: pros Less irregular astigmatism Less chance of perforation Convenient technique

Easy to perform Intraoperatively

Astigmatic Correction: LRI / AK

LRI: cons Limited astigmatic correction Regression Variability of results

Astigmatic Correction: LRI

Instruments: simple kit Axis marker 0.12-caliber forceps Diamond knife

Preset (600 microns)Micrometer

STUDY

46 eyes, 30 patients (age: 72 + 10 A)• 3.2 mm CCI, Steep axis• Preset 600 µ diamond knife• Limbal relaxing incisions• Preop Corneal Astig.: 1.66 + 0.65 D (0.75 to 3)• Follow up: 6 M

Results:Astigmatism pre / postop

Corneal Astigmatism (D)Corneal Astigmatism (D)

LRIs: Tips & Tricks

Placement of incisions• Axis

– 10° off: -33%– 15° off: -52%

• Constant orientation• Constant depth• Preset 600µ knife• Micrometer knife set at 90%

thinnest pachymetry • Steep axis +++

Astigmatic Correction withToric IOLs

Reduction of Astigmatism

SN60T3 = 1.5D (1D) SN60T4 = 2.25D (1.5D) SN60T5 = 3.0D (2D)

Astigmatic Correction withToric IOLs

FDA Data

92% 20/40 or better Mean residual astigmatism: 0.60 D 50% less than 0.5D of residual postop astigmatism 97.6% rotated less than 15 degrees

Astigmatic Correction with Laser

Laser Vision Correction: Precise correction of astigmatismCorrection of spherical componentCheck MR and WF refraction

Astigmatic Correction with Laser

n=206n=139

n=340

Netto et al, AJO 2006;141:360-368Netto et al, AJO 2006;141:360-368

Laser Astigmatic Vision CorrectionRefractive patients: primary choice

PRK LASIK Excellent accuracy (sphere & cylinder) Constant technological improvements

Laser Astigmatic Vision CorrectionAll types of regular astigmatisms

Simple, compound myopic astig. Flatten the steepest meridian

Simple, compound hyperopic astig. Steepen the flattest meridian

Mixed astig. Combine both principles

Angle Error (Degrees)

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

30.0%

35.0%

0 1 2 3 4 5 6 7 8 9 10

Angle Error (Degrees)

Undercorrection in Astigmatism

Cyclotorsion & Astigmatic Correction

ACE

SRET DRETStatic Rotational ET Dynamic Rotational ETCompensation between Intraoperative compensationupright / supine position

Iris Recognition

Cyclotorsion

Study EyesMean Degree Movement

Other

Febbraro et al.JCRS, 2010

70 3.4 + 2.7º up to 14º

Swami, Steinert et al, AJO, 2002

240 4.1º + 3.7º8% with over 10º of movement

Smith, Talamo, Assil, JCRS, 1994

50 - 25% over 7º of movement (up to 16º)

ACEACE SRETSRET DRETDRET

MeanMean 3.08 3.08 + 2.68 ° 2.68 ° 3.39 3.39 + 2.94° 2.94°

RangeRange -7 - +14.1°-7 - +14.1° -10.3 - +13.5°-10.3 - +13.5°

Results

Fondation A. de Fondation A. de RothschildRothschild

ParisParis

Jean-Luc Febbraro Jean-Luc Febbraro MDMD

Cyclotorsion:

Static (SRET) / Dynamic (DRET)

ACE

%%

Cyclotorsion Cyclotorsion

Mean Static (SRET) / Dynamic (DRET)


ParisParis


N:70 N:70

ACEMean Absolute Amplitude (DRET)


ParisParis


DRET Amplitude (°)DRET Amplitude (°)

Conclusion

• Surgical correction of astigmatism is a reality – Mandatory to optimize uncorrected vision– Refractive and cataract patients– Numerous surgical options


ParisParis


• Clinical significance– Accurate eye care

– IOL manufacturers (SA , Cyl.)

– Valuable information for cataract & refractive surgeons

Astigmatism evolution with age

Age / Ast.2654 patients

% Mean

20-30 years 40% 1.20 D

70-80 years 72% 1.30 D

Prevalence of astig. increases with age.

Ferrer-Blasco T. et al. Ferrer-Blasco T. et al. JCRS 2008; 34:424- JCRS 2008; 34:424-432432

To evaluate Astigmatism Distribution and Evolution in Adult Patients

Retrospective study 500 eyes of 276 patients Autorefractometer refraction & keratometry

measurements Mean interval: 8.37 +/-2.92 y (min 5-16 max)

Mean age 60.11 +/- 11.39

Age min- Age max 37-90

Gender: Male / Female 182 M / 318 F

Mean sphere -0.02 +/- 3.20

Sphere min-max -14.75 - + 7.5

Mean ocular astigmatism 0.95 +/- 0.77

Ocular astig. min-max 0.25 - 6.75

Mean corneal astigmatism 1.14 +/- 0.40

Corneal astig. min-max 0 - 6.5

Mean flat K (K1) 43.10 +/- 1.39

Mean steep K (K2) 44.11 +/- 1.48

Magnitude Ocular Astig. Corneal Astig.

≤0.5D 35.8% 33.8%

0.75 - 1D 36.6% 33.4%

1.25 - 2D 20.8% 23.8%

> 2D 6.8% 8.2%

Astigmatism DistributionAstigmatism Distribution

-0.02-0.02

Astigmatism Evolution

OCULAR OCULAR AST.AST.

visitvisit 11 visitvisit 22

CORNEAL CORNEAL AST.AST.

SPHERESPHERE

Astigmatism Evolution Age Groups Cylinder Axis

< 50 0.19 +/- 0.64D 6 +/- 17°

50-59 0.24 +/- 0.71D 12 +/- 20°

60-69 0.31 +/- 0.75D 6 +/-17°

> 70 0.28 +/- 0.89D 5 +/- 15°

ATR shift over 8 yearsATR shift over 8 years

0.26 D0.26 D

Astigmatism Evolution

Age GroupsAge Groups Study Study 500 eyes500 eyes

Reykjavic Eye Reykjavic Eye Study* 757 eyesStudy* 757 eyes

< 50 0.19 +/- 0.64 D

50-59 0.24 +/- 0.71D 0.09 +/- 0.41 D

60-69 0.31 +/- 0.75D 0.13 +/- 0.45 D

> 70 0.28 +/- 0.89D 0.22+/- 73°

All Groups O.26 D over 8 years 0.13 D over 5 years

* E. Gudmundsdottir, A. Arnarsson, F. Jonasson. Five-year refractive * E. Gudmundsdottir, A. Arnarsson, F. Jonasson. Five-year refractive changes in an adult population; Reykjavik Eye Study. changes in an adult population; Reykjavik Eye Study. Ophthalmology 2005;112, 672–677.Ophthalmology 2005;112, 672–677.

Knowledge of prevalence and evolution of astigmatism is valuable information 35% negligible astig. 35% 0.75 – 1 D 30% > 1 D 7% 2 D

Mean magnitude +/- 1 D in adults, tends to increase with age

ATR axis shift (0.13 – 0.26 D) over time, particularly in older patients

• Trend Size

Standard 3-mm incision Mini + 2.5-mm incision Micro sub 2-mm incision

Placement Scleral to limbal / clear corneal incision Superior to temporal approach

• Size IOL implantation

Monofocal, Multifocal, Accomodative, Toric IOLs Phaco platform

Phaco and I/A probes & sleeves

• Location Scleral to limbal / clear corneal incision Superior to temporal approach

• Astigmatic change Incision size Distance from visual axis Axis placement

• Astigmatic change evaluation Algebraic method (magnitude of ast.) Vector Analysis (magnitude & axis of ast.)

Standard 3-3.5-mm on axis CCI PKE

n: 172 Sup. Incision Temp. Incision

SIA 0.93 + 0.54 D 0.62 + 0.47 D

Long D. et al. Ophthalmology 1996; 103:226-232Long D. et al. Ophthalmology 1996; 103:226-232

Standard 3.2-mm on axis / temp. CCI PKE

n: 62On Axis Incision

Temporal Incision

SIA7 w PO

0.63 D 0.34 D *

Borasio E. et al. JCRS 2006; 32:565-572Borasio E. et al. JCRS 2006; 32:565-572

3-3.5-mm Incision & SIA RangeLiterature Summary

Incision Location

Superior Oblique On Axis Temporal

SIA (D) 0.60 – 1.50 0.60 – 1.29 0.60 – 0.90 0.09 – 0.44 *

Choice of Incision Location

1 Kohnen T, Koch D. Curr Opin 1 Kohnen T, Koch D. Curr Opin Ophthalmol. 1996; 7:75-80Ophthalmol. 1996; 7:75-80

Temporal Inc. Nasal Inc. Superior Inc.

1996Kohnen T, Koch D.1

ATR 0.75-1.25 D

WTR 0.75-1.25 D

2005Tejedor J, Murube

J.2

ATR < 0.75 D ATR > 0.75 D WTR >1.25 D

2009Tejedor J, Perez J.3 Negligible Ast. ATR WTR

2 Tejedor J, Murube J. Am J Ophthalmol. 2005; 139:767-7762 Tejedor J, Murube J. Am J Ophthalmol. 2005; 139:767-776

3 Tejedor J, Perez-Rodriguez J. IOVS. 2009; 50:989-9943 Tejedor J, Perez-Rodriguez J. IOVS. 2009; 50:989-994

n: 44 3.0-mm 2.2-mm

SIA 0.67 + 0.48 D 0.35 + 0.21 D *

Masket S. et al. JRS 2009; 25:21-2424Masket S. et al. JRS 2009; 25:21-2424

n: 108 C-MICS B-MICS

SIA 0.23 + 0.29 D 0.23 + 0.22 D

Wilczynski M. et al. JCRS 2009; 35:1563-69Wilczynski M. et al. JCRS 2009; 35:1563-69

STUDYEvaluate SIA Cataract Incisions

• Nonrandomized prospective series 191 eyes • Group 1: 60 eyes PKE 3.2-mm sup. CCI• Group 2: 68 eyes PKE 2.2-mm sup. CCI• Group 3: 63 eyes PKE 1.8-mm sup. CCI

• Two-plane incision with precalibrated metal knife

• Unenlarged wound for IOL implantation• Group 1: SN60WF / Akreos AO IOLs• Group 2: SN60WF / Akreos MICS IOLs• Group 3: Akreos MICS IOL

Group Arithmetic Mean Vector Mean

3.2-mm 1.02 + 0.39 D 0.77 at 10°

2.2-mm O.60 + 0.20 D 0.26 at 20°

1.8-mm O.48 + 0.10 D 0.16 at 13°

Vector Analysis Vector Analysis

StudyResults

• Desirable to know astigmatic effect of CCI• SIA depends on incision size and location.

• Significant less SIA with 1.8 / 2.2 / + 3.0-mm CCI.• SIA very limited with + 2.0-mm CCI.

• Desirable to know astigmatic effect of CCI• SIA depends on incision size and location.

• Significant less SIA with 1.8 / 2.2 / + 3.0-mm CCI.

• SIA very limited with + 2.0-mm CCI.

• Clinical implications• To minimize SIA & optimize visual rehabilitation.• Customized incision size and location (>2.8-mm) based upon preop.

astig.• Optimize UCVA with monofocal & premium IOLs.


ParisParis


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