photopigment

Scientists have long known that cells in the retina called photoreceptors are involved in how vision can adapt to darkness, but a study from investigators at Washington University School of Medicine in St. Louis and Boston University School of Medicine has uncovered a new pathway in the retina that allows the cells to adapt following exposure to bright light. The discovery could help scientists better understand human diseases that affect the retina, including age-related macular degeneration, the leading cause of blindness in Americans over the age of 50.

Courtesy photoSome blind patients, as well as some blind animals, still show pupil constriction in response to light.We use our eyes to see, but a good deal of recent research has demonstrated that the eyes are responsible for other functions, too. Russell N. Van Gelder, M.D., Ph.D., assistant professor of ophthalmology and visual sciences and of molecular biology and pharmacology at Washington University School of Medicine in St. Louis, has teamed with researchers at several other institutions to learn more about the eye’s second, non-visual system that is important to the body’s internal clock, as well as to other functions such as hormone release. Studying mice, the research team found that even in blind animals, it is important for the eye’s non-visual system to continue working. They believe damage to this system in the eye may contribute to several health problems in humans, even in people with normal vision.