Juvenile Macular Degeneration: Stargardt's and Best Disease
Stargardt Disease continued...
Stargardt disease does not cause a loss of peripheral, or side, vision. Most people don't lose night vision, but may have trouble adjusting between dark and light environments. Color vision is also affected in later stages of the disease.
Stargardt disease. Researchers have identified a specific gene that they believe causes Stargardt disease. If both parents carry one mutated gene and one normal gene, their children have a 25% chance of developing the disease. People who inherit only one mutated gene don't develop the disease. However, they can pass on the disease without knowing it.
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.