July 31 (HealthDay News) -- A gene associated with the formation of age-related cataract, a leading cause of blindness, has been identified by scientists.

The EphA2 gene encodes an enzyme that plays a role in the repair of damaged proteins in the eye. Expression of the EphA2 gene decreases with age, which means damaged proteins can clump together and cause the eye lens to become cloudy, resulting in obscured vision, according to the study in the July 31 issue of the journal PLoS Genetics.

The international group of researchers, including a team from Case Western Reserve University in Cleveland, have identified several mutations in the EphA2 gene that are associated with age-related cataract. They plan to search for more mutations.

Identifying the underlying causes of age-related cataract may help lead to new treatments and even ways to prevent the condition, the study authors noted.

By the time they're 80 years old, more than half of Americans will have a cataract or have had cataract surgery, according to a news release about the study.

SOURCE: Case Western Reserve University, news release, July 30, 2009