The retina contains light sensitive cells called rods and cones. Cones respond to light wavelengths that enable us to see color and are most numerous in an area of the retina called the macula which we use for our sharpest vision. Degeneration or dystrophy of the macula therefore leads to vision loss as well as difficulties with color perception.
Visual difficulties and changes in color vision in pattern dystrophies of the macula are usually noted by young adults in their 20s or 30s. Patients may notice distortion of vision or small blind spots. Changes in the retina may be seen earlier, even when vision is still normal. This is a progressive disease and vision often deteriorates to legal blindness in the range of 20/200. Night vision is not affected.
Macular dystrophy is the name applied to a group of disorders that primarily affect the macula of the retina. Many of these are inherited and numerous mutations are responsible. Most are inherited as autosomal dominant traits and appear in a vertical pattern in family trees. An affected parent passes on the mutation on average to half of his or her children.
The diagnosis of macular dystrophy can only be made by an ophthalmologist. There are no systemic abnormalities and lifespan is not impacted. Because the visible abnormalities in the retina are non-specific, your eye doctor often requests a special test known as an electroretinogram or ERG which may help determine the exact nature of the rod and cone disease. Unfortunately, no treatment is available for the dystrophy but low vision aids can aid visual function.