Wg Cdr Malcolm Woodcock
RAF Ophthalmology
Centre for Defence Medicine
University Hospital Birmingham, UK
AVIATION AVIATION OPHTHALMOLOGY 2OPHTHALMOLOGY 2
MEDICAL FACTORSMEDICAL FACTORS
Ocular Adenexae
• Blepheritis
• Chalazion
• Epiphora
• Orbital Blowout fracture
External eye disease
• 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
Eyelid disease
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)
Blowout Fracture
Patient is looking up. Loss of infraorbital sensation and subcutaneous crepitus are useful signs.
Opacification of maxillary sinus with entrapment of inferior rectus / its attachments.
Anterior Segment
• Episcleritis
• Recurrent Erosion Syndrome
• Keratoconjunctivitis sicca
• Ketatitis (microbial, adenoviral, herpetic)
• Keratoconnus
• Uveitis
• Ocular hypertension and glaucoma
• Cataract
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
Viral Keratitis
• 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
Keratoconus
• Corneal ectactic disease
• Conical cornea
• Management– Glasses– Hard contact lenses– Penetrating keratoplasty
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
PK for keratoconus
Penetrating keratoplasty
• Visual rehabilitation uncertain– Astigmatism – Rejection– Graft failure
• May require permanent topical medication
• Aircrew unfit agile aircaft / ejection
Uveitis
• 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
Glaucoma
• 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
POAG
• Visual field loss– Monitored– Flying category depends on this
• Treatment– Medical (Beta Blockers safe in aircrew)– Surgical (ALT / Trabeculectomy)
Cataract
• 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
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
Amblyopia
• ‘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
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)
Monocular aircrew
• 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
Corneal disease
• Keratoconus
• Keratitis– Viral– Bacterial
• Corneal grafts
Micro-detonator cord Splatter(MDC)
• Occurs during ejection
• May cause skin tattooing
• Corneal burns possible
• Ophthalmic examination if ocular pain or reduced VA
Harrier
Ejection
Vitreoretinal Conditions
• Floaters, holes and detachments
• Central Serous retinopathy
• Retinovascular disease
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
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
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)
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
Complications of scleral explants
• Myopia – Especially if encirclement
• Astigmatism• Extraocular muscle damage
– Diplopia
• Suture complications– Retinal perforation– Extrusion
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
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
Factors affecting fitness to fly
• Visual acuity (Macula on/off)• Visual field
– Variable effects
• Distortion– ERM– Retinal translocation
• Refraction• Diplopia
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
Retinal detachment
Before
After
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
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
Macular degeneration
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
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
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
Neurophthalmic disease
• 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)
Optic nerve atrophy and drusen
Laser eye injury
• Ocular hazard of modern warfare
• Increasing incidence of laser incidents
• Dazzle
• Glare
• Retinal damage
• Fright!!
Laser guided bomb
Wg Cdr Malcolm Woodcock
Department of Ophthalmology
Worcestershire Royal Hospital
Tel: 07891 655845
Contact details
• Wg Cdr Robert A.H. Scott– RAF Consultant Adviser in Ophthalmology– Centre for Defence Medicine, Selly Oak
Hospital, Raddlebarn Rd, B’ham B29 6JD– 0121 627 8535 (Sec) / 8922 (Fax)– [email protected]
