Stargardt Disease is the most common form of Inherited Macular Degeneration in patients under the age of 20. It is usually first noticeable between the ages of 8 and 12.
Diagnosis and cause
In this condition, the cone cells (at the macula) deteriorate in function and eventually die, while the rod cells generally remain intact. The diagnosis is usually made as a result of deterioration in visual acuity and typical appearances around the macula when the ophthalmologist looks into the eye. Electrical tests - such as the electro-retinogram (ERG), electro-oculogram and dark adaption testing - can measure the progress of the disease but are not usually necessary for its diagnosis.
Patients with previously normal vision develop irregularly shaped yellowish-white flecks or spots in the macula. This causes decreased central vision, reading and fine handwork may become difficult which eventually deteriorates to 6/60 as the flecks in the macula grow. In late stages of the disease, there may also be some impairment of colour vision.
In some, this deterioration is rapid, while in others it is much slower. There is no way to detect how fast this deterioration will occur in any individual. By the age of 50, about half will have a visual acuity of 6/60 or worse (defined as "legal blindness").
People with Stargardt disease do not usually have a problem with peripheral vision, and hence usually have little problem with bumping into objects when moving around. They may however experience difficulties in adjusting to light.
This is mainly inherited as autosomal recessive.
The gene for this disease has been located to the shortarm of Chromosome 1. The gene has recently been identified as the ABCR gene. The protein produced by this gene is involved in the energy transport to and from the photoreceptor cells.
Occasionally, it can be inherited as autosomal dominant.
Click here for Genetic Inheritance.
There is no cure, but research on this and other related diseases may identify a form of treatment.