Corneal dystrophy, microcystic

A disorder in which the cornea (the normally clear front window of the eye) shows dots (or microcysts), geographic map-like lines, and grayish fingerprint lines on examination with a slit-lamp, a device that focuses a high intensity light beam as a slit while the examiner looks at the front of the eye through a magnifying scope.</P> The disorder is usually silent and without symptoms.

However, about one patient in ten has recurrent erosion of the cornea that usually begins after the age 30.</P> Conversely, half of patients with recurrent corneal erosions of idiopathic (unknown) origin have this disorder.</P> Under the microscope, a structure called the epithelial basement membrane is abnormal.

The disorder is therefore sometimes called epithelial basement corneal dystrophy.</P> The disorder was first described by Cogan and colleagues in 1964. Hence, the name: Cogan corneal dystrophy.

It is also known, to add to the confusion, as map-dot-fingerprint type corneal dystrophy.