microcystic epithelial dystrophy

Corneal Dystrophy, Lisch Epithelial

Clinical Characteristics
Ocular Features: 

Of the anterior epithelial dystrophies, this one is unusual in the absence of spontaneous corneal erosions.  It is also the only one of this group to be an X-linked disorder.  Onset occurs in childhood and by adulthood vision can be significantly reduced.  Most individuals, however, retain vision in the range of 20/25 to 20/40 into the 7th and 8th decades.  Gray, feathery opacities in the anterior cornea often appear in a band-like or whorled pattern.  Vacuolization of the epithelial cells is responsible for this appearance but in Lisch dystrophy, these microcysts are empty compared to Reis-Bucklers, epithelial basement membrane, and Thiel-Behnke anterior dystrophies in which degenerative debris fills them.  In spite of the X-linked inheritance pattern, both males and carrier females may have similar corneal opacities since the mutation is dominant.

Systemic Features: 

No systemic disease is associated with Lisch epithelial dystrophy.

Genetics

Corneal opacities are seen in both sexes, and no father to son transmission has been reported.  This is a dominant X-linked disorder resulting from a mutation on the X chromosome (Xp22.3).  No responsible gene has been identified.

Pedigree: 
X-linked dominant, father affected
X-linked dominant, mother affected
Treatment
Treatment Options: 

The major clinical problem in this disorder is a reduction of vision in adults.  Epithelial debridement offers a temporary improvement in vision but the opacities recur within months. Soft contact lenses have been reported to reduce the epithelial opacities over several months of wear.  Discontinuation of wear can be followed by a return of the epithelial opacities.

References
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