MECD

Meesmann corneal dystrophy is a disorder of the epithelium and its basement membrane.  Onset is early, even in the first year of life and begins with irritation and often photophobia.  However, some patients remain asymptomatic for many years.  Vision is usually impacted only to a mild degree as a result of surface irregularities and epithelial cysts, which are concentrated most commonly in the interpalpebral regions.  They may only be visible with slit lamp examination. The cysts are usually in the basal cells and are filled with PAS positive material. They may coalesce to form refractile lines and later in life become more opaque. The basement membrane appears coarse and is often abnormally thick.  Bowman layer and the stroma are unaffected.  Corneal sensitivity is reduced.

Stocker-Holt dystrophy (122100) is often lumped with Meesmann dystrophy and, while it is a clinically similar disease, it is usually caused by a different mutation.  The 20 patients reported by Stocker and Holt in 1954 were descendents from Moravia who settled in North Carolina (Meesmann and Wilke's report in 1939 was based on patients in Holstein, Germany).