A group for anyone who has or knows someone who has congenital achromatopsia.

Achromatopsia is a rare hereditary vision disorder which affects 1 person in 33,000 in the U. S.

Persons who have achromatopsia do not have normal "cone vision." In the retinas of normal eyes there are 6 million cone photoreceptors, located mostly at the center of the retina. There are complete and incomplete forms of achromatopsia. Persons with complete achromatopsia must rely on their "rod vision." In the normal eye there are 100 million rod photoreceptors. Rods are located mostly at the periphery of the retina. Rods "saturate" at higher levels of illumination. Therefore, the eyes of achromats, are not able to adapt normally to higher levels of illumination. Rods do not provide color vision or good detail vision. Therefore, persons with achromatopsia are either totally colorblind or almost totally colorblind, and they have poor visual acuity. There are many variations in the severity of these manifestations among individual achromats.