corneal dystrophies

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Corneal Dystrophies, congenital anomaliesWafa Asfour FRSC

DystrophiesBilateral Symmetric inherited condition Has little or no relationship to environmental or systemic factors Tend to be slowly progressive Begin early in life but may not become clinically apparent until later Classification according to : severity, genetic, pattern, histo-pathologic features or anatomical location

Anterior Corneal DystrophiesCorneal Epithelial dystrophy (EBMD) Map-dot-fingerprint or Cogan Most common anterior corneal dystrophy Autosomal dominant with incomplete penetration 6-18% of population, commoner in women and > 5o years of age Thickened basement membrane with extension into epithelium, abnormal epithelial cells with microcysts with absent or abnormal hemidesmosomes, fibrillar material between basement membrane and bowman layer

Clinical findings:Age of onset of signs is probably 3rd decade while age of onset of symptoms is either 3rd or 4th decade of life It is often asymptomatic, otherwise painful recurrent erosions, recur over several years with gradual reduction in frequency Slit lamp signs most common and earliest change is a maplike pattern, best seen with sclerotic scatter, retroillumination or broad beam Dots are fine, grey, round or comma shaped opacities seen deep to or bordering on maps Fingerprints are rarest appear as concentric curved lines

Map-finger-dot epithelial dystrophy Fine fibrillary line in a patient with anterior membrane dystrophy

Light MicroscopyMaps: an abnormal basement membrane within the epithelial layer separating it into anterior and posterior lamellae Dots: Pseudocysts containing nuclear and cytoplasmic depris in the midepithelial layer Fingerprints: are projections of basement membrane onto overling epithelium

Management:5% Nacl ointment/ lubricants Epithelial debridement Patching /BCL

Meesmann DystrophyRare bilateral Autosomal dystrophy Appears early in life Degenerated epithelial cells> producing frequent mitosis> thickened basement membrane , basal epithelial cells. Have higher glucose, filamentary materials peculiar substance, tiny epithelial vesicles are seen most easily with retro-illumination extending out to limbus most numerous in the inter-palpebral area

Corneal dystrophy of Bowman s layerCDB type I (Reis-bucklers dystrophy) is Autosomal dominant has been linked to chromosome 5q 31 In same region as (lattice, Avellino, Granular) Reis Buckler s dystrophy: geographic has rod-shaped bodies in the region of Bowman s, similar to superficial variant of granular dystrophy CDB type II (Theil-Behnke dystrophy) is associated with chromosome 10q 24 Honeycomb-shaped, or Theil-Behnke, dystrophy has {curly fibers}

REIS BUCKLERS DYSTROPHYAutosomal dominant A bilaterally symmetrical dystrophy predominantly affecting Bowman s layer of the central cornea Age of onset of signs and symptoms 1st decade Present as: Recurrent attacks of photophobia and irritation. Subsequently progressive visual loss due to: 1, anterior corneal opacification 2. irregular astigmatism Recurrent erosions(3 or 4 episodes per year) gradually diminishing in frequency over 3 decades


Thiel- Behnke

Slit lamp signsFine reticular opacification at the level of Bowman s layer Irregular corneal surface Largely grey white opacities in the subepithelial layer these may be linear, geographic, ringlike, honeycomb, fishnet or alveolar It tends to spare periphery The irregularity of corneal surface help to distinguish from Granular

Light microscopy

fibrous tissue between epithelium and Bowman;s layer resulting in a saw tooth configuration of epithelium eventually replaces Bowman s layer Masson s trichrome

Lattice DystrophyOne of the three classic stromal dystrophies most commonly characterised by branching refractile lines as suggested by it s name. Lattice dystrophy type I is the classic type without systemic involvement, while type II is associated with systemic amyloidosis Age of onset of symptoms and signs: usually in the first decade but sometimes the fourth decade or later Usually presents as recurrent erosions or diminished vision, occasionally asymptomatic

Slit lamp signsStarts in the anterior and middle central stroma with glassy translucent dots followed by translucent lattice lines Spectrum of changes is broad and the classic branching lattice figures may not be present The dots are not dissimilar to those found in granular dystrophy stroma in between the opacitiesis generally clear, can take on a diffuse ground glass appearance with progression of disease The peripheral cornea is said to be spared, however our clinical experience shows that peripheral cornea commonly becomes involved in later cases

An irregularity and scarring occurs as a result of recurrent erosions in early stages the translucent dots may be present without lattice lines, this can lead to difficulty in diagnosis The characteristic glassy appearance of the dots distinguish them from the grey white opacities seen in granular dystrophy, the opacities in granular tend to have irregular margins and some have relatively clear centers The clarity of the intervening stroma distinguishes it from macular dystrophy Recurrent erosions in lattice dystrophy lead to central subepithelial scarring which may be confused with Reis Bucklers , however by this stage the typical branching lattice lines are present

Light microscopy1. Irregular epithelium 2. Thickened basement membrane 3. Large fusiform eosinophilic deposits in stroma A. stain red with congo red B. manifest green birefringence with a polarising microscope C. display dichroism D. fluoresce with thioflavin T and Ultraviolet light

Associations:Lattice dystrophy may be associated with systemic amyloidosis. In this case it is called lattice dystrophy type II onset of stromal dystrophy tends to be later, the erosions less frequent, vision less affected than in lattice dystrophy type I without systemic involvement Systemic involvement is characterised by cranial neuropathy, peripheral neuropathy, and skin masses Lattice type II: fewer lattice lines and a greater involvement of peripheral cornea Autosomal Dominant

Granular DystrophyOne of the three classic stromal dystrophies it is characterized by discrete grey white deposits in the central anterior stroma The intervening stroma is essentially clear and vision is not affected until late stages Age of onset of signs is first decade while symptoms start in third decade or later Most patients are asymptomatic mild photophobia may be present due to scattering of light by the opacities. recurrent erosions are very unusual, vision is usually not affected until the fifth decade

Slit lamp signsDiscrete grey white dots or radial lines in the anterior central stroma The opacities enlarge, multiply and coalesce with time they gradually extend deeper into the stroma and further peripherally with time , however the peripheral 2-3 mm of the cornea are always spared making the distinction from macular dystrophy easy, the stroma in between the opacities remains clear Light microscopy: eosinophilic rod or trapezoidal deposits in the anterior stroma, these stain red with Masson s trichrome Autosomal dominant

Advanced Granular Dystrophy

Advanced Granular Dystrophy

Avellino Dystrophy (Granular Lattice)

A variant of granular dystrophy, was originally described in a small number of famillies who traced their roots to Avellino, Itally

Avellino corneal dystrophyIt is also present in other countries; in Japan, it may be more common than lattice The affected patients have a granular dystrophy both histologically and clinically, with lattice lesions in addition to the granular lesions Older patients have anterior stromal haze between deposits which reduces visual acuity Pathologically both the hyaline deposits typical of granular dystrophy and the amyloid deposits typical of lattice dystrophy

Clinical profile of Avellino corneal dystrophy in British families

Clinical and genetic profile of Avellino corneal dystrophy in 2 families from North India

Clinical and genetic profile of Avellino corneal dystrophy in 2 families from North India

Clinical and genetic profile of Avellino corneal dystrophy in 2 families from North India

Clinical and genetic profile of Avellino corneal dystrophy in 2 families from North India

Clinical and genetic profile of Avellino corneal dystrophy in 2 families from North India

Severe form of corneal stromal dystrophy in 5 Japanese patients

Clinical profile of Avellino corneal dystrophy in British families

Association of Keratoconus and Avellino Corneal Dystrophy

Macular DystrophyIs the rarest of the three classical stromal dystrophies Uniquely it is inherited in an autosomal recessive manner Characterized by multiple irregular grey white opacities in the superficial central corneal stroma with a diffuse stromal haze in between the lesions Age of onset of signs and symptoms is the first decade

Macular Dystrophy

presentationPhotophobia is a prominent feature, out of proportion to the signs Deterioration in vision occurs early, usually by 20 to 30 years of age Penetrating keratoplasty is required Recurrent erosions may occur but are much less frequent than in lattice dystrophy

Slit lamp signsEarlier changes are a central, faint ground glass haze in the superficial stroma, Later multiple small grey white opacities with irregular borders develop within this superficial haze. Opacities are most dense centrally peripheral cornea is not spared the opacities may enlarge and take on a nodular appearance Descemet s membrane may take on a slate grey appearance and multiple corneal guttae may be seen until the stromal opacification precludes thei


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