Corneal dystrophy, Cogan

A disorder in which the cornea (the normally clear front window of the eye) shows grayish fingerprint lines, geographic map-like lines, and dots (or microcysts) on examination with a slit-lamp 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 descriptively (to add to the confusion) as map-dot-fingerprint type corneal dystrophy and microcystic corneal dystrophy.