Study of Dark Adaptation in Age-Related Macular Degeneration

Background: * Age-related macular degeneration (AMD) is a leading cause of vision loss in individuals over 55 years of age. It can cause permanent loss of central vision, which is important for seeing fine details and long distances. AMD has two forms: wet AMD and dry AMD. Most people with AMD have dry AMD. But dry AMD can progress to wet AMD. Wet AMD is the more serious form and can result in severe vision loss. * A method to identify and monitor the early to middle stages of AMD may help researchers develop new treatments to stop the disease before it becomes severe. In early dry AMD, people cannot see well at night. Researchers want to study whether a procedure that measures how the eye adjusts to the dark can help to identify and monitor early to middle dry AMD. Objectives: \- To evaluate the effectiveness of using a dark adaptation protocol to identify and monitor early to middle dry age-related macular degeneration. Eligibility: \- People at least 50 years of age who have no AMD. Others who have early to middle dry AMD in at least one eye. Design: * People will be screened with a physical examination, medical history, blood and urine tests, and a full eye exam. * This study will last 5 years and require at least 9 visits to NIH. (First visit; study visits at months 3, 6, 12, 18, and 24; and 3 yearly followup visits). * Up to 10 people will be asked to come back to the clinic 1 week after their first visit. They will be asked to test the device to be used in the study. * Participants will have baseline exams. These questions will be about problems that affect their eyes under different lighting conditions. * At every visit, participants will answer questions about general health and current medications (including any vitamins or supplements). They will also have a full eye exam and a 20- to 40-minute test. This test measures how fast the eyes recover in response to decreasing levels of light. The test also measures how sensitive the eyes are to these con