Aviation OphthalmologyAviation Ophthalmology
Wg Cdr Malcolm Woodcock Wg Cdr Malcolm Woodcock
RAF OphthalmologyRAF Ophthalmology
Royal Centre for Defence Royal Centre for Defence MedicineMedicine
Should we correct the vision of Should we correct the vision of military aircrew surgically?military aircrew surgically?
Wg Cdr Malcolm Woodcock Wg Cdr Malcolm Woodcock
RAF OphthalmologyRAF Ophthalmology
Royal Centre for Defence MedicineRoyal Centre for Defence Medicine
OROR
What about laser eye What about laser eye surgery Doc?surgery Doc?
IntroductionIntroduction
Vision is the most important sense needed Vision is the most important sense needed for flying for flying
Vision is the only sensory means for Vision is the only sensory means for orientation in spaceorientation in space
Two steps in visionTwo steps in vision– At the eyeAt the eye– In the brainIn the brain
VA Helps PilotsVA Helps Pilotsat Combined Velocity of 1,200 Mphat Combined Velocity of 1,200 Mph
VA Recognition Distance Time to collision
6/6 3 miles 4.5 sec
6/4 4 miles 6.0 sec
6/3 6 miles 9.0 sec
90% thickness90% thicknesskeratotomykeratotomy
Radial keratotomy (RK)Radial keratotomy (RK)
Diurnal variationDiurnal variation Variation with altitudeVariation with altitude RegressionRegression Weakened corneaWeakened cornea Unsuitable for aircrewUnsuitable for aircrew
Photorefractive Keratectomy (PRK)Photorefractive Keratectomy (PRK)
Pros and Cons of PRKPros and Cons of PRK
71-92% no glasses71-92% no glasses 88% rate vision good 88% rate vision good
to excellentto excellent
RegressionRegression– 1-9% retreatment1-9% retreatment– Related to level of Related to level of
myopiamyopia Variable refraction up Variable refraction up
to 1 yearto 1 year 11% dissatisfied11% dissatisfied
Specific Complications of PRKSpecific Complications of PRK
Painful due to de-Painful due to de-epithelialisationepithelialisation
Corneal stromal Corneal stromal hazehaze– Reduced corneal Reduced corneal
sensitivitysensitivity– 1.5-3.2% lose >2 Sn 1.5-3.2% lose >2 Sn
lineslines
Ablation edge Ablation edge effectseffects– Halos (night driving)Halos (night driving)– Decentred ablation Decentred ablation
Laser In-situ Keratomilieusis (Lasik)Laser In-situ Keratomilieusis (Lasik)
Corneal flap
Pros and cons of LasikPros and cons of Lasik
Reduced hazeReduced haze– Bowman’s layer Bowman’s layer
preservedpreserved Increased ablation Increased ablation
areaarea– decentration less decentration less
problemproblem– Higher myopes treatedHigher myopes treated
PainlessPainless– No de-epithelialisationNo de-epithelialisation
Flap loss / damageFlap loss / damage– Ejection riskEjection risk– Trauma riskTrauma risk
Unknown time to flap Unknown time to flap stabilitystability
Retinal detachmentRetinal detachment– Suction ringSuction ring
Sands of SaharaSands of Sahara
LASIK LASIK vs.vs. PRK PRK
Flap decentration of lasikFlap decentration of lasik Raised IOP of lasikRaised IOP of lasik Pain of PRKPain of PRK Equal correction of myopia 1-3 dioptresEqual correction of myopia 1-3 dioptres Lasik more accurate 3-6 dioptresLasik more accurate 3-6 dioptres SE of glare, halos, reduced night visionSE of glare, halos, reduced night vision
– Different proportions but equal effectsDifferent proportions but equal effects
US Navy ExperienceUS Navy Experience
30/30 naval aviators av –3.25d30/30 naval aviators av –3.25d– All achieved 20/20 unaidedAll achieved 20/20 unaided– Glare / halo transient Glare / halo transient – Night vision worse (1 declined other eye)Night vision worse (1 declined other eye)
No effects on NFL of PRKNo effects on NFL of PRK African Americans have excellent outcomesAfrican Americans have excellent outcomes No effect on PRK from ejectionNo effect on PRK from ejection
– NFO S-3B VikingNFO S-3B Viking
Schallhorn SC et al. Preliminary results of PRK in active duty United States Navy personnel. Ophthalmology 1996 Jan;103(1):5-27.
USN PRK Study 2002USN PRK Study 2002
1035 patients1035 patients 84% no gls 4 weeks84% no gls 4 weeks 95% 6/6 or better95% 6/6 or better 99% 6/9 or better99% 6/9 or better
150 pilots150 pilots Target recognition Target recognition
– 98% better98% better– 2% worse2% worse
82% better carrier 82% better carrier landinglanding
98% better instrument 98% better instrument readingreading
Schallhorn S, Tanzer D, Fulton D. Update on refractive surgery in Naval aviation. Presented at the Aerospace Medical Association 73rd annual meeting, Montreal, Canada, May 2002.
USAF PRK studyUSAF PRK study
80 subjects 20 80 subjects 20 controlscontrols
20% required 20% required correction postopcorrection postop– Aimed for –0.5d Aimed for –0.5d
postop refractionpostop refraction
No effect from altitudeNo effect from altitude No effect from G No effect from G
loadingloading No decrease in HUD No decrease in HUD
readabilityreadability
Tredici T, Ivan D Results and conclusions of the USAF Photorefractive Keratectomy (PRK) study. Presented at the Aerospace Medical Association 73rd annual meeting, Montreal, Canada, May 2002.
Other TechniquesOther Techniques
Clear lens extractionClear lens extraction– For high myopesFor high myopes– Danger of RDDanger of RD
Phakic intraocular lensesPhakic intraocular lenses– May cause lens opacitiesMay cause lens opacities
LASLASEEKK– PRK without the painPRK without the pain
Current State of Play for Civilian Current State of Play for Civilian ApplicantsApplicants JAR class 1 certificationJAR class 1 certification
– Preoperative refraction + 5.00 to -6.00 dioptresPreoperative refraction + 5.00 to -6.00 dioptres– Must be examined by eye specialist at CAA medical Must be examined by eye specialist at CAA medical
div Gatwickdiv Gatwick– 1 year before certification 1 year before certification
JAR class 2 certificationJAR class 2 certification– Preoperative refraction +5.00 to -8.00 dioptresPreoperative refraction +5.00 to -8.00 dioptres– Ophthalmic report about surgery and its results to Ophthalmic report about surgery and its results to
AMEAME– 1 year before certification1 year before certification
Current Pilots – When Can They Fly?Current Pilots – When Can They Fly?
JAR class 1 recertificationJAR class 1 recertification– Must be examined by eye specialist at CAA Must be examined by eye specialist at CAA
medical div Gatwickmedical div Gatwick• Stable refractionStable refraction
– 6/12 to 1 year before certification 6/12 to 1 year before certification
Class 2 recertificationClass 2 recertification– Ophthalmic report about surgery and its Ophthalmic report about surgery and its
results to AMEresults to AME
RAF Refractive Surgery (Currently!)RAF Refractive Surgery (Currently!)
Cost to be borne by the Cost to be borne by the individualindividual
To be performed under To be performed under conditions of strict audit by conditions of strict audit by DMS consultantsDMS consultants
To incorporate latest wavefront To incorporate latest wavefront technologytechnology
Grounded for 6/12-1 year until Grounded for 6/12-1 year until refraction stablerefraction stable
Not accepted in recruitsNot accepted in recruits
Post-operativelyPost-operatively
Snellen Visual acuitySnellen Visual acuity RefractionRefraction Contrast acuity Contrast acuity
analysis (CAA)analysis (CAA)
Super Vision!!!Super Vision!!!
Monochromatic Monochromatic aberrationsaberrations
Visual potential lies Visual potential lies between 6/3 – 6/2between 6/3 – 6/2
Wavefront Optics for AstronomyWavefront Optics for Astronomy
Asteroid 4 Vesta
Magnified Star Milky Way
Pueo star field
Correction of atmospheric aberrations
Wavefront AnalyserWavefront Analyser
Wavefront ImagesWavefront Images
What if it goes wrong? What if it goes wrong?
Well, that’s toughWell, that’s tough
Risks of significantly Risks of significantly reduced vision reduced vision extremely smallextremely small
That risk borne by That risk borne by individualindividual
No compensationNo compensation Remedial treatment Remedial treatment
not taken onnot taken on
CongenitalCongenitalColour Vision DefectsColour Vision Defects
Sex linked red / greenSex linked red / green Blue / yellow very rare Blue / yellow very rare
(Homozygotic)(Homozygotic) Current tests are for Current tests are for
red / green defectsred / green defects
Acquired Colour Vision DefectsAcquired Colour Vision Defects
Predominantly affects blue / green discriminationPredominantly affects blue / green discrimination DiseaseDisease
– Macular blue / yellowMacular blue / yellow– Optic nerve red / greenOptic nerve red / green
Drugs Drugs – Inc alcohol, tobacco and OCPInc alcohol, tobacco and OCP– ‘‘Viagra blue’Viagra blue’
Old ageOld age
Electronic Flight Electronic Flight Instrumentation Systems (EFIS)Instrumentation Systems (EFIS)
Increase information Increase information to aircrew through to aircrew through use of coloured use of coloured screensscreens
Use blues and Use blues and yellows as best yellows as best contrasting colours for contrasting colours for normal visionnormal vision
EFIS IssuesEFIS Issues
Effect of colour vision Effect of colour vision defects uncertaindefects uncertain– Colour anomalousColour anomalous– Acquired defects Acquired defects – No research No research
Blue / yellow testing?Blue / yellow testing?– Periodic for acquired Periodic for acquired
defects?defects?
Holmes Wright LanternHolmes Wright Lantern
No longer madeNo longer made Long term replacement neededLong term replacement needed Fletcher CAM test a possibility but not Fletcher CAM test a possibility but not
fully tested or validatedfully tested or validated
ConclusionsConclusions
Medical standards Medical standards required to maintain required to maintain air safety in the face air safety in the face ofof– Changing technologyChanging technology– Changing experienceChanging experience
Wg Cdr Malcolm WoodcockWg Cdr Malcolm Woodcock
Department of OphthalmologyDepartment of Ophthalmology
Worcestershire Royal HospitalWorcestershire Royal Hospital
Tel: 07891 655845Tel: 07891 655845
[email protected]@doctors.org.uk
Wg Cdr Robert A.H. ScottWg Cdr Robert A.H. Scott
Defence Consultant Adviser in Ophthalmology Defence Consultant Adviser in Ophthalmology Royal Centre for Defence Medicine Royal Centre for Defence Medicine Selly Oak Hospital Selly Oak Hospital
Raddlebarn Road Raddlebarn Road
BirminghamB29 6JD BirminghamB29 6JD
0121-627- 85350121-627- 8535
0121-627- 8922 0121-627- 8922
[email protected]@lineone.net
