Choroidal dystrophies

Choroideremia; Gyrate atrophy; Central areolar choroidal dystrophy

Choroidal dystrophies are eye disorders that involve a layer of blood vessels called the choroid. These vessels are between the sclera (the white of the eye) and retina (the black of the eye).

In most cases, a choroidal dystrophy is due to an abnormal gene, which is passed down through families. It most often affects males, starting in childhood.

The first symptoms are peripheral vision loss and vision loss at night. An eye doctor who specializes in the retina (back of the eye) can diagnose this disorder.

External and internal eye anatomy

The cornea allows light to enter the eye. As light passes through the eye the iris changes shape by expanding and letting more light through or constricting and letting less light through to change pupil size. The lens then changes shape to allow the accurate focusing of light on the retina. Light excites photoreceptors that eventually, through a chemical process, transmit nerve signals through the optic nerve to the brain. The brain processes these nerve impulses into sight.

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