Usher Syndrome

Usher syndrome is characterized by hearing loss or deafness and progressive vision loss due to retinitis pigmentosa (RP). RP is a condition that affects the retina (the part of the eye that detects light and color). Some people with the condition also have balance problems due to a defect in that part of the inner ear that controls balance. Genetic changes are related to the following types of Usher syndrome. Usher syndrome type I Usher syndrome type II Usher syndrome type III Hearing and vision losses are the major features of Usher syndrome. Type I and type III can also include difficulties with balance due to inner ear problems. The signs and symptoms vary in their severity and age of onset (most are present from birth or shortly thereafter, while others begin later in childhood). All types of Usher syndrome have progressive vision loss due to retinitis pigmentosa (RP), a condition in which deterioration occurs in the retina. The retina is a light-sensitive cell layer in the back of the eye that contains rod cells for night vision and cone cells for seeing color and detail during the day. Night vision loss begins first, and then blind spots develop in the side (peripheral) vision. These spots enlarge and merge into a doughnut shape, producing tunnel vision. Central vision is reduced and blurs but, in some cases, may be very limited but sharp for many years. Cataracts may develop in the teenage years or in adulthood