Other Degenerative Diseases

Choroideremia

Choroideremia is a rare hereditary disease that is characterized by progressive degeneration of various layers of cells in the back of the eye, namely the retina, the choroid and the retinal pigment epithelium (RPE). Usually the loss of vision first appears as an irregular ring that gradually expands in both directions in the visual field. Since the disease is inherted by a x-(gender-linked)chromosome, it affects almost exclusively males.

Stargardt's Disease

Stargardt's disease is the most common form of juvenile macular degeneration. As in AMD, central vision is affected while peripheral vision remains largely intact. The disease is usually inherited in an autosomal recessive manner, which means that both parents carry one healthy and one affected gene each. The disease will develop only if a child receives two affected genes from the parents (in 25% of cases).

Best's Disease

Best's Disease - also known as vitelliform macular dystrophy - is characterized by a loss of central vision similar to that seen in other forms of macular degeneration. Usually the disease is diagnosed in childhood. In the initial stages, a bright yellow cyst (fluid-filled sac) forms under the retinal pigment epithelium (RPE) beneath the macula which looks like a freid egg with the "sunny-side-up." Despite this condition, visual acuity may remain normal or sufficient for many years. In many cases the cyst eventually ruptures, which causes further vision loss. However, Best's Disease does not always affect both eyes; sometimes it does not progress far enough to cause severe loss of vision. The disease follows an autosomal dominant pattern of inheritance, i.e. one affected gene suffices for the condition to develop.

Treatable Forms of RP

Some rare variations of retinitis pigmentosa such as gyrate atrophy, refsum disease, Bassen-Kornzweig syndrome (abetalipoproteinanemia) can be treated today with special diets since the underlying metabolic mechanism is known.
For more information on the forms of retinal degeneration mentioned on this page, please visit the Foundation Fighting Blindness at http://www.blindness.org/visiondisorders/causes.asp