Download Miscellaneous corneal conditions (Imp for UGs)

Corneal dystrophies & other
miscellaneous corneal
conditions
MBBS
KGMU
Common corneal disorders
• Keratitis/ corneal ulcer.
• Corneal trauma.
• Keratomalacia.
• Ectatic conditions.
• Corneal dystrophies.
• Corneal degenerations.
Differences between dystrophy &
degeneration
Corneal dystrophy
• Bilaterally symmetrical.
• Often hereditary.
• Limited to a particular corneal
layer.
• Non-inflammatory.
Corneal degeneration
• Non-hereditary.
• Usually unilateral sometimes
bilateral.
• Not strictly limited to a
particular corneal layer.
• Non inflammatory
Corneal dystrophies
Corneal Dystrophies
• Epithelial & sub-epithelial.
• Bowman’s membrane.
• Stromal.
• Endothelial.
Epithelial, sub-epith & Bowman’s corneal
dystrophies
• Epithelial & sub-epithelial – manifest in adults.
• Epithelial basement membrane dystrophy.
• Meesman dystrophy.
• Bowman’s layer dystrophies – manifest in childhood.
• Thiel Behnke corneal dystrophy.
• Reis-Bucklers corneal dystrophy.
Comparison between epithelial, subepithelial, Bowman’s dystrophies
• Similarities:
• Symptoms:
• Asymptomatic / associated with recurrent corneal erosions.
• Foreign body sensation & watering.
• Treatment by PTK –photo-therapeutic keratectomy by EXCIMER
LASER.
• Difference:
Slit lamp examination shows patterns typical for each one.
Meesman’s dystrophy (intra-epithelial
microcystic appearance)
Stromal Dystrophies
• Granular form
• Lattice form
• Macular form Bilateral.
Manifest at puberty.
Diminution of vision is the presenting complaint.
Central cornea.
Granular stromal dystrophy
AD. Crumb-like accumulation of hyaline material
Lattice dystrophy
(AD. Criss-cross lines).
Macular Dystophy
AR Opacities dispersed throughout stroma.
Endothelial dystrophies
• Fuchs endothelial dystrophy – AD. Elderly.
• CHED – Congenital hereditary endothelial
dystrophy. AD/AR.
• PPMD –Posterior polymorphous dystrophy. AD.
Features common to all endothelial
dystrophies
• Limbus-to-limbus corneal clouding
• Bilateral.
• Endothelium is attenuated or even absent
• Oedematous cornea may be 2-3 times normal thickness.
• Generalised haze or diffuse ground glass appearance.
• Photophobia and lacrimation in late stages due to bullous
keratopathy.
Specular microscopy in endothelial dystrophy
Normal endothelim
Decreased cell count, pleomorphism,
polymegathism
Congenital hereditary endothelial dystrophy
(CHED)
• Autosomal dominant (later in infancy).
• Autosomal recessive
• Earlier presentation (at birth; nystagmus).
CHED
Posterior polymorphous dystrophy
• Autosomal dominant.
• Bilateral.
• 2nd or 3rd decade….rarely -in early infancy.
• Vesicle like lesions in non-banded part of Descemet’s membrane.
• Periph ant synechiae & raised IOP may be present.
Management of endothelial dystrophies
• Specular microscopy – for endothelial cell count.
• Pachymetry –corneal thickness.
Treatment required if symptomatic.
Symptomatic treatment:
• Hypertonic saline eye drops.
• Bandage contact lens.
Definitive treatment:
Endothelial keratoplasty (DSAEK).
Penetrating keratoplasty.
Corneal degenerations
Corneal degenerations
• Arcus senilis / juvenilis.
• Band shaped keratopathy.
• Terriens marginal degeneration.
• Salzmann nodular degeneration.
• Spheroidal degeneration.
Arcus senilis
Terrien marginal degeneration
• Bilateral.
• Progressive thinning of superior
peripheral cornea.
• No inflammation.
• Presents with myopia or
astigmatism.
Band shaped keratopathy
• Horizontal opacification in
palpebral aperture.
• Chronic uveitis, silicon oil.
• Blind shrunken eyes.
• Hyperparathyroidism,
sarcoidosis.
• Treatment – chelation with
EDTA.
• PTK ??
Ectatic conditions
Ectatic conditions
(non inflammatory)
• Keratoconus.
• Pellucid marginal degeneration.
• Keratoglobus.
Keratoconus
• Congenital weakess of corneal collagen.
• Conical shape of cornea because of central thinning and bulging
(Munson sign).
• Manifests after puberty.
• High myopia & astigmatism.
• Treatment options:
• Rigid contact lens.
• Corneal cross linking (C3R).
• Keratoplasty.
Keratoconus
Pellucid marginal degeneration
• Painless bilateral thinning of inferior peripheral cornea.
• Myopia & astigmatism.
• It is probably a variant of keratoconus.
Keratomalacia
Keratomalacia
• Bilateral.
• Rapidly increasing clouding of
cornea.
• No congestion.
• Melting of cornea.
• Night blindness +/• Other features of malnutrition /
diarrhoea.
• Timely injecs of Vit A & control of
malnutrition.
Corneal injuries
• Best possible repair also ends up
in subnormal visual gain.
• Timely keratoplasty is required in
visually significant opacity to
prevent amblyopia.
• Donor tissue selection should be
very carefully done - good
endothelial count.
Need of the hour
• Proper education of medical personnel, school teachers and health
workers regarding causes and prevention of childhood blindness.
• Training of medical personnel at primary and secondary health care
centres regarding early diagnosis of treatable conditions and suitable
management.
• To know ‘when to refer’ to higher centre.
• Over-the-counter sale of corticosteroid eye drops to be stopped.
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