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Wg Cdr Malcolm Woodcock RAF Ophthalmology Centre for Defence Medicine

AVIATION OPHTHALMOLOGY 2 MEDICAL FACTORS. Wg Cdr Malcolm Woodcock RAF Ophthalmology Centre for Defence Medicine University Hospital Birmingham, UK. Ocular Adenexae. Blepheritis Chalazion Epiphora Orbital Blowout fracture. Blepharitis Lid hygiene Topical/systemic tetracycline

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Wg Cdr Malcolm Woodcock RAF Ophthalmology Centre for Defence Medicine

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  1. AVIATION OPHTHALMOLOGY 2MEDICAL FACTORS Wg Cdr Malcolm Woodcock RAF Ophthalmology Centre for Defence Medicine University Hospital Birmingham, UK

  2. Ocular Adenexae • Blepheritis • Chalazion • Epiphora • Orbital Blowout fracture

  3. Blepharitis Lid hygiene Topical/systemic tetracycline Dry eye (keratoconjunctivitis sicca) Ocular lubricants Ocular allergic disease Mast cell stabilisation (Na Chromoglycate) Topical steroids Systemic antihistamines A bar to flight training External eye disease

  4. Eyelid disease

  5. Epiphora (Watery Eye) • Reflex – corneal or conjunctival irritation • Obstructive – mechanical obstruction of nasolacrimal drainage system • Functional – Failure of lacrimal pump system through lack of tone in lower lid (ectropion, VII nerve palsy)

  6. Blowout Fracture Opacification of maxillary sinus with entrapment of inferior rectus / its attachments. Patient is looking up. Loss of infraorbital sensation and subcutaneous crepitus are useful signs.

  7. Anterior Segment • Episcleritis • Recurrent Erosion Syndrome • Keratoconjunctivitis sicca • Ketatitis (microbial, adenoviral, herpetic) • Keratoconnus • Uveitis • Ocular hypertension and glaucoma • Cataract

  8. Bacterial keratitis • Serious ocular infection • Requires admission and expert management • Treatment • Corneal scrape and culture • Topical antibiotics • Visual result depends on amount and position of retinal scarring

  9. HSV keratitis Dendritic ulcer Topical Aciclovir Metherpetic disease 20-25% (Disciform keratitis) Top Aciclovir/steroids Oral Aciclovir 1yr (not aircrew despite RCT) Adenoviral keratitis Follicular keratoconjunctivitis Highly infectious Corneal stromal opacities Can affect optic axis May require topical steroids Viral Keratitis

  10. Keratoconus • Corneal ectactic disease • Conical cornea • Management • Glasses • Hard contact lenses • Penetrating keratoplasty

  11. Keratoconus in aircrew • Often develops in teens to 20s • ‘Forme fruste’ of keratoconus may be present in aircrew applicants • No test for progression • Piggy-back CL hard centre with soft surround • Possible use in fast-jet aircrew • Not tested yet

  12. PK for keratoconus

  13. Penetrating keratoplasty • Visual rehabilitation uncertain • Astigmatism • Rejection • Graft failure • May require permanent topical medication • Aircrew unfit agile aircaft / ejection

  14. Inflammation of eye Idiopathic Infectious Systemic disease Anterior Intermediate Posterior Pan-uveitis Treatment Topical / systemic Anterior uveitis often controlled with topical steroids Flying category usually preserved with limitations Systemic immunosuppression Uveitis

  15. Uveitis

  16. POAG Syndrome of characteristic optic neuropathy associated with a raised IOP Familial ACG Acute glaucoma associated with narrow iridocorneal angles Ocular hypertension Not galucoma risk of POAG Retinal vascular occlusion Glaucoma

  17. POAG • Visual field loss • Monitored • Flying category depends on this • Treatment • Medical (Beta Blockers safe in aircrew) • Surgical (ALT / Trabeculectomy)

  18. Lens opacity Congenital Acquired Treat if symptomatic In aircrew Usually congenital Trauma / Surgery Inflammation (Fuchs) Metabolic (DM) Drugs (Steroids) Small inscision surg Phacoemulsification Micronuclear Rapid rehabilitation Tiny corneal scar IOL PMA / Acrylic / Si Same SG as aqueous Ejection / vibration should be safe Cataract

  19. Phacoemulsification in aircrew • 5 Aircrew operated on for LO • Traumatic 3 • Inflammatory 1 • Congenital 1 • All achieved 6/6 VA • All fit flying • 2 Fast Jet • 2 Helicopter • 1 Transport

  20. ‘Where the Doctor and patient sees nothing’ Central suppression of image to avoid diplopia Visual maturation by age 7 Associated Strabismus Anisometropia Visual deprivation Refractive Treatment with patching as child Untreatable as adult Important if good eye lost Amblyopia

  21. Strabismus • Concomitant • Childhood • A bar to aircrew entry unless • Alternate with good vision on each side • Microtropia (test stereopsis) • Incomitant • Extraocular muscle palsy • Often diplopia (prisms / surgery)

  22. Reduced stereopsis Reduced field of vision Blind spot USA FAA No difference in accident rate between uniocular and binocular pilots Usually restricted to fly as or with qualified co-pilot Monocular aircrew

  23. Corneal disease • Keratoconus • Keratitis • Viral • Bacterial • Corneal grafts

  24. Micro-detonator cord Splatter(MDC) • Occurs during ejection • May cause skin tattooing • Corneal burns possible • Ophthalmic examination if ocular pain or reduced VA

  25. Harrier Ejection

  26. Vitreoretinal Conditions • Floaters, holes and detachments • Central Serous retinopathy • Retinovascular disease

  27. Vitreoretinal disease • Posterior vitreous detachment • Retinal detachment (1:10,000) • External repair (Cryopexy/scleral buckle) • Internal repair (Vitrectomy/laser/cryopexy/internal tamponade) • Intraocular tamponade agents

  28. Posterior vitreous detachment(PVD) • Separation of vitreous gel from retina • Flashes and floaters (Weis ring) • Abnormal VR adhesion (haemorrhage, tears) • 65% by 65yrs • Earlier if Myopic • If acute symptomatic 10% risk retinal tear • Indirect ophthalmoscopy with indentation • Laser retinopexy if necessary

  29. Symptomatic floater in flyer! • Navigator 36 yo emmetropic (LVA 6/5) • 6 month history left floater • Left PVD, prominent Weiss ring • Felt unsafe to fly as kept on thinking aircraft closing in periphery • Left vitrectomy (uncomplicated) • Kept full flying category • No problems at 1 year (Minimal myopic shift)

  30. Complications of vitrectomy • Entry site iatrogenic retinal breaks • 2-4% in simple vitrectomy • Risk of retinal detachment • Index myopia and cataract formation • Nuclear sclerosis accelerated in all cases • 75% cataract extraction by 3 years if gas used

  31. Complications of scleral explants • Myopia • Especially if encirclement • Astigmatism • Extraocular muscle damage • Diplopia • Suture complications • Retinal perforation • Extrusion

  32. Gas intraocular tamponade • Posturing required for 1-2 weeks • Gases • Air 2 days • SF6 2 weeks • C3F8 2 months • No sight until bubble above optical axis • Boyles law expansion of bubble if atmospheric pressure decreases • Decompression danger with >10% gas in eye

  33. Si oil intraocular tamponade • Permanent tamponade • Non-expansile • No immediate visual loss • Less posturing • Hypermetropic shift (+6 dioptres) • Less IOP regulation • increased effects of G forces

  34. Factors affecting fitness to fly • Visual acuity (Macula on/off) • Visual field • Variable effects • Distortion • ERM • Retinal translocation • Refraction • Diplopia

  35. Case of RD in Chinook pilot • 45 y.o. pilot • Crash 1985 • BK amputation left leg • Facial trauma • Routine eye test left visual field defect • VAL 6/6

  36. Retinal detachment Before After

  37. Outcome • Visual field became full • VAL remained at 6/6 • Fit full flying duties • Must have at least 2 legs and 3 eyes in the cockpit

  38. Retinal degeneration • Congenital / acquired • Age related maculopathy • Dry /exudative • Macular drusen common • Commonest cause of blindness in UK • Hereditary retinal dystrophy • End stage often macular degeneration

  39. Macular degeneration

  40. Centroserous Retinopathy • Localised serous chorioretinal detachment • Unknown aetiology • Early mid-aged males affected • VA slightly reduced (hypermetropia) • Diagnosis confirmed on FFA • Spontaeneous resolution the rule • Hastened by laser • Slight residual decrease in VA

  41. Amaurosis fugax • Transient uniocular loss of vision <10 mins • Embolic • Carotid artery • Cardiac • Hyperviscosity states • Cranial arteritis • Flying category depends on treatment of underlying disease

  42. Central Retinal Vein Occlusion • Sudden painless visual impairment • Disc oedema and scattered retinal haems • Risk factors: Age, hypertension, smoking, obesity, blood dyscrasias • Seen in a subset of younger patients • Poorer prognosis if it becomes ischaemic

  43. Optic neuritis Reduced VA (6/18-6/60) Central scotoma Impaired colour vision Ocular pain 75% develop MS 70% recover 6/6 in 8 weeks Optic disc drusen Incidental finding Visual field defects Nystagmus Physiological Congenital Acquired (always needs further investigation) Neurophthalmic disease

  44. Optic nerve atrophy and drusen

  45. Laser eye injury • Ocular hazard of modern warfare • Increasing incidence of laser incidents • Dazzle • Glare • Retinal damage • Fright!!

  46. Laser guided bomb

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