Hereditary forms of macular degeneration, which affect children and young adults, are much less common than age-related macular degeneration. Retinitis pigmentosa is a hereditary disease which results in reduction or loss of night vision and peripheral vision. The peripheral region of the retina, which is rich in the light-sensing rod cells, becomes damaged. The rods detect light by means of their light-sensitive pigment protein, rhodopsin. In some families exhibiting retinitis pigmentosa, various mutations have been found in the gene encoding rhodopsin.
Macular degeneration can result in central vision blindness.
The appearance of drusen spots on the macula, possibly drusen accompanied by some scarring of the macula, is referred to by ophthalmologists as maculopathy or macular dystrophy. There is evidence that people with drusen spots, especially large drusen spots, have an increased likelihood of developing macular degeneration, which is usually diagnosed when central vision has begun to deteriorate. Cone dystrophy is a genetic disorder which typically affects one of the three classes of cones rather than generally affecting rods and cones in the macula, as macular degeneration does. Cone dystrophy is often misdiagnosed as macular degeneration. Central serous retinopathy is sometimes misdiagnosed as macular degeneration.