Corneal dystrophies & other miscellaneous corneal conditions MBBS KGMU
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Miscellaneous corneal conditions (Imp for UGs)
Corneal dystrophies & other miscellaneous corneal conditionsMBBSKGMUCommon corneal disordersKeratitis/ corneal ulcer.Corneal trauma.Keratomalacia.Ectatic conditions.Corneal dystrophies.Corneal degenerations.
Differences between dystrophy & degenerationCorneal dystrophyBilaterally symmetrical.Often hereditary.Limited to a particular corneal layer.Non-inflammatory.
Corneal degenerationNon-hereditary.Usually unilateral sometimes bilateral.Not strictly limited to a particular corneal layer.Non inflammatory
Corneal dystrophiesCorneal DystrophiesEpithelial & sub-epithelial.
Endothelial.Epithelial, sub-epith & Bowmans corneal dystrophiesEpithelial & sub-epithelial manifest in adults.Epithelial basement membrane dystrophy.Meesman dystrophy.
Bowmans layer dystrophies manifest in childhood.Thiel Behnke corneal dystrophy.Reis-Bucklers corneal dystrophy.Comparison between epithelial, sub-epithelial, Bowmans dystrophiesSimilarities: 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.
Meesmans dystrophy (intra-epithelial microcystic appearance)
Stromal DystrophiesGranular 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 DystophyAR Opacities dispersed throughout stroma.
Endothelial dystrophiesFuchs endothelial dystrophy AD. Elderly.
CHED Congenital hereditary endothelial dystrophy. AD/AR.
PPMD Posterior polymorphous dystrophy. AD.Features common to all endothelial dystrophiesLimbus-to-limbus corneal cloudingBilateral.Endothelium is attenuated or even absentOedematous cornea may be 2-3 times normal thickness.Generalised hazeor diffuse ground glass appearance. Photophobia and lacrimation in late stages due to bullous keratopathy.
Specular microscopy in endothelial dystrophyNormal endothelimDecreased cell count, pleomorphism, polymegathism
Congenital hereditary endothelial dystrophy(CHED)Autosomal dominant (later in infancy).Autosomal recessiveEarlier presentation (at birth; nystagmus).CHED
Posterior polymorphous dystrophyAutosomal dominant.Bilateral.2nd or 3rd decade.rarely -in early infancy.Vesicle like lesions in non-banded part of Descemets membrane.Periph ant synechiae & raised IOP may be present.Management of endothelial dystrophiesSpecular 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 degenerationsCorneal degenerationsArcus senilis / juvenilis.Band shaped keratopathy.Terriens marginal degeneration.Salzmann nodular degeneration.Spheroidal degeneration.Arcus senilis
Terrien marginal degenerationBilateral.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 conditionsEctatic conditions(non inflammatory)Keratoconus.
Pellucid marginal degeneration.
KeratoconusCongenital 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.
Pellucid marginal degenerationPainless bilateral thinning of inferior peripheral cornea.Myopia & astigmatism.It is probably a variant of keratoconus.KeratomalaciaKeratomalaciaBilateral.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 injuriesBest 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 hourProper 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.Do your best always
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