Definition of Fuchs' dystrophy:

Fuchs' (pronounced Fooks) dystrophy is an eye disease in which cells lining the inner surface of the cornea slowly start to die off. The disease usually affects both eyes.

Causes, incidence, and risk factors:

Fuchs' dystrophy can be inherited, which means it can be passed down from parents to children. In some families, it is inherited in an autosomal dominant manner. That means that if either of your parents has the disease, you have a 50% chance of developing the condition.

However, the condition may also occur in persons without a known family history of the disease.

Fuchs' dystrophy is more common in women than in men. Vision problems usually do not appear before age 50, although doctors may be able to see signs of the disease in affected persons at an earlier age, usually in their 30s and 40s.

Fuchs' dystrophy affects the thin layer of cells that line the back part of the cornea. This layer is called the endothelium. The disease occurs when these cells slowly start to die off. (The cause is unknown.) The cells help pump excess fluid out of the cornea. As more and more cells are lost, fluid begins to build up in the cornea, causing swelling and a cloudy cornea.

At first, fluid may build up only during sleep, when the eye is closed. As the disease gets worse, small blisters may form in the endothelium. The blisters get bigger and may eventually break, causing eye pain. Fuchs' dystrophy can also cause the shape of the cornea to change, causing further vision problems.