Cogan's Dystrophy (Map-Dot-Fingerprint Dystrophy)
Cogan's Dystrophy is a disease that affects the cornea. It is commonly
called Map-Dot-Fingerprint Dystrophy because of microscopic dot and
fingerprint-like patterns that form within the layers of the cornea.
The cornea is comprised of five layers. Cogan's affects the
superficial cornea layer called the epithelium. The epithelium's bottom,
or basement layer of cells becomes thickened and uneven. This weakens
the bond between the cells and sometimes causes the epithelium to become
loosened and slough off in areas. This problem is called corneal
erosion.
Even though this disease is commonly known as a
dystrophy (a term that describes genetic diseases), Cogan's is not
necessarily an inherited problem. It often affects both eyes and is
typically diagnosed after the age of 30. Cogan's usually becomes
progressively worse with age.
SIGNS AND SYMPTOMS
Some
patients with Cogan's dystrophy have no symptoms at all. The symptoms
among patients may may vary widely in severity and include:
•Light sensitivity
•Glare
•Fluctuating vision
•Blurred vision
•Irregular astigmatism (uneven corneal surface)
•Mild to extreme
irritation and discomfort that is worse in the morning
DETECTION AND
DIAGNOSIS
The doctor examines the layers of the cornea with a slit
lamp microscope. In some cases, corneal topography may be needed to
evaluate and monitor astigmatism resulting from the disease.
TREATMENT
The treatment for Cogan's is dependent on the severity of
the problem. The first step is to lubricate the cornea with artificial
tears to keep the surface smooth and comfortable. Lubricating ointments
are recommended at bedtime so the eyes are more comfortable in the
morning. Salt solution drops or ointments such as sodium chloride are
often prescribed to reduce swelling and improve vision. Gas permeable
contacts are occasionally fit for patients with irregular astigmatism to
create a smooth, even corneal surface and improve vision.
For
patients with recurrent corneal erosion, soft, bandage contact lenses
may be used to keep the eye comfortable and allow the cornea to heal. In
some cases, laser treatment may beneficial. The surgeon removes the
epithelium with an Excimer laser, creating a regular, smooth surface.
The epithelium quickly regenerates, usually within a matter of days,
forming a better bond with the underlying cell layer.
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