Usher Syndrome Type III is milder than type 1, but still causes progressive hearing loss and vision loss. Hearing is often normal at birth with progressive hearing loss typically beginning during childhood or early adolescence. Vision loss due to retinitis pigmentosa begins to develop in adolescence, and is also progressive, often leading to blindness by adulthood. The rate of decline of hearing and vision can vary from person to person.

A mutation in the CLRN1 gene, located on chromosome #3 has a carrier frequency of 1 in 107 in the Ashkenazi Jewish population. Currently, there is no treatment for Usher Syndrome Type III but hearing loss can be managed with hearing aids and possible cochlear implant.