Presentation is loading. Please wait.

Presentation is loading. Please wait.

Aviation Ophthalmology

Similar presentations

Presentation on theme: "Aviation Ophthalmology"— Presentation transcript:

1 Aviation Ophthalmology
Wg Cdr Malcolm Woodcock RAF Ophthalmology Royal Centre for Defence Medicine

2 Should we correct the vision of military aircrew surgically?
Wg Cdr Malcolm Woodcock RAF Ophthalmology Royal Centre for Defence Medicine

3 What about laser eye surgery Doc?
OR What about laser eye surgery Doc?

4 Introduction Vision is the most important sense needed for flying
Vision is the only sensory means for orientation in space Two steps in vision At the eye In the brain

5 VA Helps Pilots at Combined Velocity of 1,200 Mph

6 Radial keratotomy (RK)
90% thickness keratotomy Diurnal variation Variation with altitude Regression Weakened cornea Unsuitable for aircrew

7 Photorefractive Keratectomy (PRK)

8 Pros and Cons of PRK 71-92% no glasses
88% rate vision good to excellent Regression 1-9% retreatment Related to level of myopia Variable refraction up to 1 year 11% dissatisfied

9 Specific Complications of PRK
Ablation edge effects Halos (night driving) Decentred ablation Painful due to de-epithelialisation Corneal stromal haze Reduced corneal sensitivity % lose >2 Sn lines

10 Laser In-situ Keratomilieusis (Lasik)
Corneal flap

11 Pros and cons of Lasik Reduced haze Increased ablation area Painless
Bowman’s layer preserved Increased ablation area decentration less problem Higher myopes treated Painless No de-epithelialisation Flap loss / damage Ejection risk Trauma risk Unknown time to flap stability Retinal detachment Suction ring Sands of Sahara Diffuse Lamellar Keratitis - Non-severe forms have been estimated to occur in 1% of cases; severe cases comprise only about 1 in 5,000 surgeries.5 A number of names including Sands of the Sahara have been used to describe this condition, which is characterized by an accumulation of inflammatory cells under the flap. The condition usually appears at one to three days after LASIK. However, there have been recent reports of late onset DLK.6-7 Multiple causes have been hypothesized, but no single explanation accounts for all cases. Rx intensive topical steroids. 5. Steinert, RF. Swami, AU. Diffuse Interface Keratitis. Review of Refractive Surgery, January 6. Yeoh J, Moshegor CN. Delayed diffuse lamellar keratitis after laser in situ keratomileusis. Clin Experiment Ophthalmol 2001 Dec;29(6): Chang-Godinich A, Steinert RS, Wu HK. Late occurrence of diffuse lamellar keratitis after laser in situ keratomileusis. Arch Ophthalmol 2001 Jul;119(7):1074-6

12 LASIK vs. PRK Flap decentration of lasik Raised IOP of lasik
Pain of PRK Equal correction of myopia 1-3 dioptres Lasik more accurate 3-6 dioptres SE of glare, halos, reduced night vision Different proportions but equal effects

13 US Navy Experience 30/30 naval aviators av –3.25d
All achieved 20/20 unaided Glare / halo transient Night vision worse (1 declined other eye) No effects on NFL of PRK African Americans have excellent outcomes No effect on PRK from ejection NFO 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.

14 USN PRK Study 2002 1035 patients 84% no gls 4 weeks 95% 6/6 or better
150 pilots Target recognition 98% better 2% worse 82% better carrier landing 98% better instrument reading 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.

15 USAF PRK study 80 subjects 20 controls 20% required correction postop
Aimed for –0.5d postop refraction No effect from altitude No effect from G loading No decrease in HUD readability 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.

16 Other Techniques Clear lens extraction Phakic intraocular lenses LASEK
For high myopes Danger of RD Phakic intraocular lenses May cause lens opacities LASEK PRK without the pain

17 Current State of Play for Civilian Applicants
JAR class 1 certification Preoperative refraction to dioptres Must be examined by eye specialist at CAA medical div Gatwick 1 year before certification JAR class 2 certification Preoperative refraction to dioptres Ophthalmic report about surgery and its results to AME

18 Current Pilots – When Can They Fly?
JAR class 1 recertification Must be examined by eye specialist at CAA medical div Gatwick Stable refraction 6/12 to 1 year before certification Class 2 recertification Ophthalmic report about surgery and its results to AME

19 RAF Refractive Surgery (Currently!)
Cost to be borne by the individual To be performed under conditions of strict audit by DMS consultants To incorporate latest wavefront technology Grounded for 6/12-1 year until refraction stable Not accepted in recruits Aircrew are normally recruited before ocular maturity and at an age when CRS may not provide long-term refractive stability. Furthermore, the long-term outcome of CRS in trained aircrew needs to be evaluated before considering the procedure for potential aircrew.

20 Post-operatively Snellen Visual acuity Refraction
Contrast acuity analysis (CAA)

21 Super Vision!!! Monochromatic aberrations
Visual potential lies between 6/3 – 6/2

22 Wavefront Optics for Astronomy
Correction of atmospheric aberrations Asteroid 4 Vesta Milky Way Pueo star field Magnified Star

23 Wavefront Analyser

24 Wavefront Images

25 What if it goes wrong? Well, that’s tough
Risks of significantly reduced vision extremely small That risk borne by individual No compensation Remedial treatment not taken on

26 Congenital Colour Vision Defects
Sex linked red / green Blue / yellow very rare (Homozygotic) Current tests are for red / green defects

27 Acquired Colour Vision Defects
Predominantly affects blue / green discrimination Disease Macular blue / yellow Optic nerve red / green Drugs Inc alcohol, tobacco and OCP ‘Viagra blue’ Old age

28 Electronic Flight Instrumentation Systems (EFIS)
Increase information to aircrew through use of coloured screens Use blues and yellows as best contrasting colours for normal vision

29 EFIS Issues Effect of colour vision defects uncertain
Colour anomalous Acquired defects No research Blue / yellow testing? Periodic for acquired defects?

30 Holmes Wright Lantern No longer made Long term replacement needed
Fletcher CAM test a possibility but not fully tested or validated

31 Conclusions So watch this space.....
Medical standards required to maintain air safety in the face of Changing technology Changing experience So watch this space.....

32 Wg Cdr Malcolm Woodcock
Department of Ophthalmology Worcestershire Royal Hospital Tel:

33 Wg Cdr Robert A.H. Scott Defence Consultant Adviser in Ophthalmology Royal Centre for Defence Medicine Selly Oak Hospital Raddlebarn Road BirminghamB29 6JD

Download ppt "Aviation Ophthalmology"

Similar presentations

Ads by Google