what is a dystrophy?
developmental, symmetric and frequently hereditary changes occurring in original corneal tissue because of faulty nutrition, unrelated to other systemic or local diseases
are corneal dystrophies typically autosomal dominant or recessive?
dominant - recessive are usually more serious (morbid)
what are some standard characteristics of corneal dystrophies?
autosomal dominant, onset by age 20, bilateral, slowly progressive changes, no systemic disease association, no primary ocular disease history, centrally located, primary involvement of single corneal layer
which dystrophy is an exception to the characteristic of being discovered by age 20?
Fuch's dystrophy (age-related degenerative process)
what are 3 anterior corneal dystrophies?
cogan microcystic, meesman's, ries-buckler's
what are 5 stromal corneal dystrophies?
lattice, granular/avellino, macular, schnyder's, fleck
what are 2 posterior corneal dystrophies?
Fuch's and posterior polymorphous
what is cogan microcystic (EBMD, ABMD) or "map-dot-fingerprint"?
epithelial basement membrane dystrophy - most common corneal dystrophy asymptomatic to irritation upon waking, transient VA, photophobia, glare, pain (RCE)
who typically gets cogan microcystic dystrophy?
non-hereditary = against the rule
male = females
what are the 4 different presentations for cogan microcystic dystrophy?
dots, microcysts, fingerprints (least common) and maps (most common)
what causes cogan microcystic dystrophy?
abnormal basement membrane (lacking hemidesmosomes) and abnormal attachment of BM to bowmans
what is the dot pathology for EBDM?
microcyst filled with cytoplasmic debris - trapped by extra BM material (BM becomes thickened in places and cysts become enveloped)
what is the treatment for acute EBMD?
abrasion protocol = bandage CL, pressure patch, antibiotic, NSAID, cycloplegic, doxycycline lubricants
what is the treatment for chronic EBMD?
abrasion protocol = bandage CL, pressure patch, antibiotic, NSAID, cycloplegic, doxycycline, lubricatns hypertonic = 5% NaCl gtt, ung (Muro 128)
what is Meesman's dystrophy?
rare - intraepithelial cysts (6 months) = abnormal basal cells and maturation to squamous, thick BM
what happens if the cysts in Meesman's dystrophy rupture?
pain, tearing, photophobia vision minimally affected
what is Reis-Buckler's dystrophy?
rare - painful RCE age 5-20 with decreasing episodes by 30
bowman's/anterior stroma replaced by fibrocellular tissue, irregular corneal surface, scarring, decrease/fluctuation in VA
what is lattice dystrophy (type 1)?
age 2-10, VA reduction, RCE common anterior stromal "inter-lacing" filamentous lesions, white spots, central haze (amyloid deposits)
what is lattice type 2 dystrophy?
similar phenotype but not genotype to type 1 central cornea sparing and associated with other conditions (VN7 palsy, peripheral neuropathy, amyloidosis)
what is granular dystrophy?
*earliest seen dystrophy - in first decade VA reduction > 40 y/o centrally discrete focal white deposits all stromal depths "cornflakes", area between lesions is clear (deposits are hyaline-like material) RCE is rare
what is Avellino (granular type 2) dystrophy?
unique to area of italy - features are similar to lattice and granular
what is macular dystrophy?
most severe and least common dystrophy - VA reduction starts in teens, photophobia, RCE less than lattice exception to "dystrophy rule" - AR extends to periphery
what causes macular dystrophy?
(autosomal recessive disease) excess glycosaminoglycans - abnormal keratocytes storage mucopolysaccharide
what does macular dystrophy look like?
diffuse, "ground-glass" haze lesions, corneal haze between lesions, gray/white or milky/white opacities throughout stroma and limbus to limbus
what is schnyder's central crystalline?
exception to "dystrophy rule" - associated with systemic hypercholesterolemia (cardiovascular risks)
what are the symptoms of schnyder's central crystalline dystrophy?
mild VA reduction (20/40), no RCE, central crystals from annulus during 1st to 2nd decades, dense arcus ring
what is fleck dystrophy?
gray/white opacities, odd shaped, incidental findings at all levels of the stroma
what is posterior polymorphous dystrophy (PPD)?
asymptomatic, rare reduction in VA, polymorphous opacities at level of Descemet's, maybe corneal edema
which dystrophy has a glaucoma risk?
posterior polymorphous dystrophy (PPD) - 15% may develop increased IOP (abnormal endothelium grows across TM onto iris = anterior synechiae)
why is Fuch's dystrophy an exception to the "dystrophy rule"?
exceptions to rule = higher in females (postmenopausal), age-related (>40), may extend to periphery and appears multi-layered