The primary visual symptom of Usher syndrome is loss of vision from retinitis pigmentosa, or RP.
The retina is the layer of light-sensing cells lining the back of your eye that converts light rays into nerve impulses. The impulses are sent through the optic nerve to your brain, where they are recognized as images.
With RP, cells in the retina called rods and cones gradually die due to loss of a critical factor that is not being produced. With most forms of RP, rods — which are mainly in the outer regions of the retina and are responsible for our peripheral and night vision — degenerate first. When the retina’s more centrally-located cones are affected, the result is loss of color perception and central (reading) vision. Eventually, generally after many years, blindness results.
Next Page: Usher Syndrome Diagnosis and Treatment
