corneal dystrophies

CORNEAL CORNEAL DYSTROPDYSTROPHIESHIES

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CORNEAL DYSTROPHIES:CORNEAL DYSTROPHIES:

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‘corneal dystrophy’ typically refer to a group of inherited corneal diseases that are usually bilateral, symmetric, slowly progressive and not related to environmental or systemic factors.

CLASSIFICATION The most commonly used classification

system is anatomically based.[7] The dystrophies are typically classified by level of the cornea that is involved, which separates these entities into epithelial and subepithelial, Bowman layer, stromal, and endothelial dystrophies

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CLASSIFICATION: 1.Epithelial

2.Bowman`s

3.Stromal

4.Endothelial

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Epithelial

Cogan Meesmann Lisch

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Cogan Meesman Lisch

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Type Cogan MeesmanLisch

InheritanceSporadic,ADAD AD,X-linked

SymptomRecurrent corneal erosion

Ocular irritationOcular irritation

Sign Dot-like,map-like,epithelial microcyst,finger print.

Myriad intraepithelial cyst,thin cornea,reduced sensation

Whorled configuration, micro cyst.

HistologyThickBM with deposition of fibrillary protein between BM and bowmans layer, abscent hemidesmosome

ThickBM.ThickBM.

T/t LubricantLubricantLubricant8

Theoretical pathogenesis of epithelial basement membrane dystrophy. Epithelial cells produce abnormal multilaminar basement membrane, both in normal location (1) and intraepithelially (2). As the intraepithelial basement membrane thickens, it blocks normal migration of epithelial cells toward the surface. Trapped epithelial cells degenerate to form intraepithelial microcysts (3) that slowly migrate to the surface (4). Abnormal basement membrane produces map and fingerprint changes, and microcysts produce the dot pattern seen clinically

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Parallel lines and fingerprint lines in broad slit retroillumination

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Retroillumination of epithelial basement membrane dystrophy seen as map patterns and microcysts

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Bowman

CDB1 CDB2 schnyder

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SCHNYDER

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TypeCDB1CDB2Schnyder

InheritanceADADAD

SymptomsRecurrent corneal erosion.

Recurrent corneal erosion.

↓VA,Glare.

SignsFine, round, polygonal subepithelial opacities,visual impairment due to scarring of BL.

Subepithelial opacities (honeycomb) configuration involving central cornea.

Central crystalline opacity.

HistologyB.L & B.M replaced by fibrous tissue.

B.L replaced by curly fibers.

Phospholipid & cholesterol deposition.

TreatmentLubricant,E.L keratectomy

Not necessaryE.L keratectomy

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CDB1 CDB2 SCHNYDER

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STROMAL CORNEAL DYSTROPHIES

Francois CD

Macular CD

Granular CDII

Granular CDI

Gelatinous CD

Lattice III

Lattice II

Lattice I

Stromal

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LATTICE WORK

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LATTICE DYSTROPHY

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TypeLattice ILattice IILattice III

InheritanceADADAD

SymptomsRecurrent corneal erosion

Recurrent corneal erosion

Photophobia,↓VA ,Watering.

SignsGlassy dots,fine lattice,outward spread,stromal haze,↓corn.sensation

Radial periphery located short,fine lattice lines, ↓corn.sensation.

Thick rope-like band lattice.

HistologyAmyloid deposition

Amyloid deposition

Amyloid deposition

TreatmentKeratoplasty if affect the vision.

Keratoplasty if affect the vision.

Keratoplasty if affect the vision.

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AMYLOID DEPOSIT IN MULTIPLE ORGANS CAUSE NEUROPATHY,THICK ITCHY SKIN ,PROTRUDED LIPS,CARDIAC ARRHYTHMIAS …ETC.

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MASK FACE IN AMYLOIDOSIS:

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GELATINOUS DROP-LIKE DYSTROPHY: AR inheritance.

Rare mainly affecting Japanese people so called Japanese type amyloid corneal dystrophy.

Usually presented at 1st or 2nd decade with sever photophobia , watering and visual impairment.

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GELATINOUS DROP-LIKE DYSTROPHY

Biomicroscopical examination shows:

Gray subepithelial nodules which increase in size and confluence then giving rise to Mulburry-like appearance.

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GELATINOUS DROP-LIKE DYSTROPHY

HISTOLOGY: Histologicaly there is

sub epithelial and anterior stromal deposition of amyloid.

This condition should be treated with repeated superficial keratectomy as recurrence in graft is very high.

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GRANULAR CORNEAL DYSTROPHY

GCDI GCDII(Avellino) AD AD 1st decade 2nd decade Recurrent erosion uncommon.

Rec.eros.Uncommon 25

GCD I(GROENOUW TYPE I)

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GCDI Centrally located corneal opacities

(ring,snowflake,crubms,sugar granules)not reaching limbus.

Overall appearance gives the shape of christmas tree.

Corneal sensation decrease. VA impared at advanced stage.

GCDII(granular-lattice dys.)

Centrally dense opacities (ring,disc,star,snowflake) like GCDI

Overall pattern radially spread like Lattice dystrophy .

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GCDI histology shows amorphous hyaline deposits which stain bright red with Masson trichrome.

GCDII histology shows both hyaline and amyloid in the stroma that stains with Masson trichrome and Congo red.

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GCDI has to be treated by keratoplasty usually at 5th decade when there is visual impairment while GCDII most of the time not require treatment.

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Granular dystrophy with discrete stromal opacities with intervening clear stroma and sparing of the periphery

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Slit lamp photograph demonstrating the shapes of the lesions and their primarily anterior stromal location

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Avellino corneal dystrophy there are lattice deposits in addition to the characteristic granular lesions.

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((GROENOUW TYPE IIGROENOUW TYPE II))MACULAR MACULAR DYSTROPHYDYSTROPHY )

Macular dystrophy is the least common stromal dystrophy, in which a systemic inborn error of keratan sulphate metabolism seems to have only corneal manifestations. It has been divided into clinically indistinguishable types I, IA and II depending on the presence or absence of antigenic keratan sulphate in the serum and cornea; these have been shown to be due to mutations in the same sulfotransferase gene (CHST6).

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MACULAR DYSTROPHY Histology shows

abnormally close packing of collagen in the corneal lamellae and abnormal aggregations of glycosaminoglycans which stain with Prussian blue and colloidal iron

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MACULAR DYSTROPHYMACULAR DYSTROPHY

The onset is towards the end of the 1st decade with visual deterioration.

Biomicroscopy shows: Anterior stromal haze, initially involving the central cornea. Greyish-white, dense, focal, poorly delineated spots in the anterior

stroma centrally and posterior stroma in the periphery. Superficial deposits may produce an irregularity of the corneal

surface, although recurrent erosions are unusual. Increase in size and stromal haze Increasing opacification with eventual involvement of full-thickness

stroma up to the limbus, associated with corneal thinning.Treated by keratoplasty but recurrence may occur.

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Macular dystrophy with diffuse opacification of the stroma and multiple, irregular, gray-white opacities extending to the limbus.

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Slit lamp photograph demonstrating deep peripheral lesions (1).

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Ultrasound biomicroscopy in macular dystrophy. Central cornea demonstrating anterior echo (1) epithelium and Bowman's membrane, posterior echo (2) Descemet's membrane and endothelium, and stroma containing highly reflective opacities (3) at a depth of 93 µm from the surface. 38

FRANÇOIS CENTRAL CLOUDY FRANÇOIS CENTRAL CLOUDY DYSTROPHYDYSTROPHY

1. AD Inheritance.2. Polygonal, cloudy grey opacities separated by relatively clear spaces, in the posterior stroma most prominent centrally, creating a leather-like appearance 3.The signs are similar to posterior crocodile shagreen but it is differentiated by its central, posterior location and mode of inheritance. 4. Treatment is not required.

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Endothelial

Fuchs endoth dys. Post.plymorphous dys.

Cong.hered.end.dys.

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FUCHS ENDOTHELIAL DYSTROPHY

Fuchs endothelial dystrophy)FED) is characterized by bilateral accelerated endothelial cell loss. It is more common in women and is associated with a slightly increased prevalence of open-angle glaucoma.

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FUCHS END. DYSTROPHY

1.Inheritance may occasionally be AD although the majority are sporadic.

2Onset of this slowly progressive disease is commonly in old age, although earlier onset can occur.

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Cornea guttata refers to irregular warts or ‘excrescences’ of Descemet membrane secreted by abnormal endothelial cells.

Specular reflection shows tiny dark spots caused by disruption of the regular endothelial mosaic

Progression occurs to a ‘beaten metal’ appearance which may be associated with melanin deposition.

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Endothelial decompensation gradually leads to central stromal oedema and blurred vision, worse in the morning and clearing later in the day.

Epithelial oedema develops when stromal thickness has increased by about 30%.

Persistent epithelial oedema results in the formation of microcysts and bullae (bullous keratopathy) which causes pain and discomfort on rupture, thought to be due to exposure of naked nerve endings.

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FUCHS END. DYSTROPHYFUCHS END. DYSTROPHYTREATMENTTREATMENT a Conservative options include

topical sodium chloride 5% drops or ointment, reduction of intraocular pressure and using a hair dryer to speed corneal dehydration in the morning

b Bandage contact lenses provide comfort by protecting exposed nerve endings and flattening bullae.

c Penetrating or deep lamellar endothelial keratoplasty has a high success rate and should not be delayed.

d Other options in eyes with poor visual potential include conjunctival flaps and amniotic membrane transplants.

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FUCHS END. DYSTROPHYFUCHS END. DYSTROPHY

Cataract surgery may accelerate endothelial cell loss and result in decompensation. A ‘triple triple procedureprocedure’ (cataract surgery, lens implantation and keratoplasty) should be considered in eyes with corneal epithelial oedema or when preoperative pachymetry measurement is greater than 640 µm. If corneal thickness is less than 640 µm, a good visual outcome is to be expected.

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POSTERIOR POLYMORPHOUSPOSTERIOR POLYMORPHOUS DYSTROPHYDYSTROPHY Posterior

polymorphous corneal dystrophy )PPCD) is a rare, innocuous and asymptomatic condition in which corneal end. cells display characteristics similar to epithelium.

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PPCD AD Inheritance. Symptoms start at birth or

soon thereafter, although it is most frequently identified by chance in later life.

Signs consist of subtle vesicular endothelial lesions that may become confluent band-like lesions or diffuse opacities which may be asymmetrical.

Ocular associations include iris abnormalities, glaucoma and Alport syndrome.

Treatment is not required.

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Slit lamp photomicrograph of vesicular lesion (1) in PPCD.

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Specular photomicrograph of vesicular lesions in PPCD appearing as rounded black areas that interrupt the dotted white endothelial mosaic.

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Slit lamp appearance of a linear band lesion in PPCD.

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CONGENITAL HEREDITARY CONGENITAL HEREDITARY ENDOTHELIAL DYSTROPHYENDOTHELIAL DYSTROPHY Congenital hereditary

endothelial dystrophy )CHED) is a rare dystrophy in which there is focal or generalized absence of corneal endothelium. There are two main forms, CHED1 and CHED2, the latter being more severe .

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CHEDCHED

Inheritance of CHED1 is AD with the gene locus on 20p11.2-q11.2. CHED2 is AR with the gene locus on 20p13 It starts perinatally. Microscopically there is bilateral, symmetrical, diffuse corneal oedema resulting in a blue-grey, ground-glass appearance to total opacification• Visual impairment is variable and visual acuity may surpass that expected from the corneal appearance.

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CHEDCHED Treated by penetrating keratoplasty which has a

reasonable chance of success when performed early but is risky and technically more difficult than in adults. Undue delay in surgical intervention carries the risk of dense amblyopia.

Put in your mind not to confuse CHED with other

causes of neonatal corneal opacification such as congenital glaucoma, rubella , keratitis mucopolysaccharidoses, birth trauma and sclerocornea.

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corneal dystrophies

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