ATLANTA -- In two separate studies, vision researchers at the Yerkes Primate Research Center have discovered that the visual experience of one eye influences the growth and subsequent quality of vision in the fellow eye. Previously it was believed that a problem existing in one eye -- a cataract or nearsightedness for instance -- would have no ill effect on the other, normal eye. These studies, reported in the January issue of Investigative Ophthalmology & Visual Science and the upcoming May issue of Vision Research add to the growing evidence that from infancy, visual development is influenced by a control system integrating the two eyes which is dependent on environmental, not merely genetic factors.
Discovering how this interocular control system works is a major step oward the prevention of problems like nearsightedness, or myopia -- a condition affecting approximately 25 percent of the U.S. population and costing billions of dollars per year in treatment. Preventing myopia during the developmental stage would enable more people to achieve accurate focus without wearing eyeglasses or having corrective surgery, the effects of which are not always permanent.
Though the work was done in monkeys, the results have eventual clinical applications for humans, according to Drs. Dolores Bradley and Alcides Fernandes, co-investigators of the studies. Dr. Bradley, a vision research scientist and Dr. Fernandes, a pediatric ophthalmologist, use monkeys as models for conditions affecting the visual system in children. Their findings suggest that infants should have their eyes checked in the first year of life so that a problem in one eye can be detected early and prevent disrupting the growth of the fellow eye. Parents often wait until their children reach school age to have their eyes checked, but by then subtle problems in one eye may have already damaged the healthy eye as well.