The eye is a complex organ that is responsible for detecting light and color and turning these visual cues into images. Most hereditary eye diseases affect the structure of the eye called the retina, which is a nerve layer on the back of the eye that is made up of rods and cones. Rods and cones are photoreceptor cells that aid in light and color detection. Hereditary eye diseases that affect these structures may be mild or cause future vision problems.
Retinitis Pigmentosa
Retinitis pigmentosa is an inherited eye disease that causes degeneration of the retina, the part of the eye that is responsible for visual images. The disease is caused by mutated genes that are inherited by only one or both parents. The mutated genes signal the rods and cones to make incorrect types or amounts of a certain protein that is responsible for proper eye function. In those with retinitis pigmentosa, the rods and cones gradually die, causing a decrease in vision. In most forms of retinitis pigmentosa, the rods, which are responsible for dim light vision, are affected first. This results in an initial loss of peripheral and night vision. When the cones eventually become affected, loss of color vision and central vision occurs. Most people with retinitis pigmentosa are legally blind by the age of 40, according to the Foundation Fighting Blindness. As of 2010, treatment options for retinitis pigmentosa are still being researched.
Achromatopsia
Achromatopsia is an inherited vision disorder that is characterized by decreased vision, sensitivity to light and the absence of color vision. Achromatopsia is caused by a chromosome abnormality that results in nonfunctioning cones. The disease is inherited from both parents, who each carry one part of a diseased gene that must come together to form the disorder, according to the American Association for Pediatric Opthalmology and Strabismus. Parents who carry the diseased genes do not develop achromatopsia. Treatment for achromatopsia consists of refractive lenses that can improve vision. Lenses can improve vision problems but do not completely correct them. Dark-tinted or red-tinted glasses may also be worn to decrease sensitivity to light. Achromatopsia is non-progressive, which means it does not worsen over time.
Color Blindness
Color blindness is a genetic eye problem that results in the inability to see color in a normal way. Color blindness is caused by problems with the color-sensing pigments in the cones. The most common type of color blindness is characterized by the inability to distinguish between the colors red and green and is caused by the absence of a single pigment. Other forms of color blindness present difficulties in distinguishing between the colors blue and yellow. Color blindness affects approximately one in 10 men and is very rare in women, according to MedlinePlus. Color blindness is a lifelong condition for which there is no treatment available. Most people are able to adjust to the condition without difficulty.
