Juvenile Macular Degeneration: Stargardt's and Best Disease
The second most common type of JMD is called Best disease, or Best vitelliform macular dystrophy. It was discovered in 1905 by Friedrich Best, a German ophthalmologist. The disease can be detected between ages 3 and 15 years old, although symptoms may not develop until later.
Signs of Best disease. Best disease appears as a bright yellow fluid-filled sac, or cyst, under the macula. The cyst looks like a sunny-side-up egg. Vision may be normal or near normal at this stage. Eventually the sac bursts, and the fluid spreads throughout the macula.
Best disease symptoms. The disease occurs in stages over a period of years. In early stages, there is no loss of vision. During later stages, the disease causes central vision loss in one or both eyes. Symptoms include blurred and distorted vision. Central vision may deteriorate to about 20/100 in later stages. Some people with Best disease never progress to later stages and may not have serious vision loss. Others may lose vision in one eye, but not the other.
Genetics of Best disease. If one parent has Best disease and one does not, there is still a 50% chance that their children will inherit the disease. Children who do not develop the disease can't pass it on to their children.
Juvenile retinoschisis, also called X-linked retinoschisis, occurs primarily in young males. Vision loss tends to occur between age 10 and 20 and then remains stable until age 50 to 60.
Signs of juvenile retinoschisis. This condition causes the retina to split into two layers in the macula. Blisters and blood vessels fill the space between these layers. The blood vessels leak blood into the vitreous fluid. This is the clear fluid that fills the inside of the eye. Eventually, the vitreous fluid may pull away from the retina. The retina may also detach from the inside wall of the eye.
Juvenile retinoschisis symptoms. The eye disease causes central vision loss ranging from 20/60 to 20/120. Symptoms also may include difficulty focusing both eyes on one object, (strabismus), and involuntary eye movements (nystagmus). About half of people with the disease lose side vision. By age 60 or older, vision loss may reach 20/200.
Genetics of Juvenile retinoschisis. The abnormal gene that causes retinoschisis is linked to the X chromosome. Women who carry the abnormal gene have a 50% chance of passing it to their daughters, who will become carriers. They also have a 50% chance of passing it to their sons, who then get the disease. Men with the disease will always pass the disease gene to their daughters, who then become carriers. Men can't pass the gene to their sons.
As with other types of juvenile macular degeneration, there is no treatment for this juvenile retinoschisis. However, surgery can help repair detached retinas.