Visual Motor Coordination

Background: * The relation between eye movement and brain function is a subject of interest to the National Eye Institute. * By comparing eye movement in healthy volunteers to research conducted on patients who have difficulty moving their eyes, the National Eye Institute hopes to develop and improve diagnostic procedures for people with eye diseases. Objectives: -The purpose of this study is to understand how we see visual patterns and how we move our eyes to see. Eligibility: * Normal volunteers: * must have no serious illnesses and must be 18 years of age or older * are able to follow directions and pay attention to visual stimuli and respond as appropriate * individuals with a history of eye or brain diseases, or previous eye or eye muscle surgery, are not allowed to participate in this study. Individuals who are currently using eye medications also are not eligible for the study. * Patients: * who are 18 years of age or older * are able to follow directions and pay attention to visual stimuli and respond as appropriate Design: * Participants will visit the National Eye Institute outpatient clinic for examination and testing. * Participants will be screened with a medical history and eye examination (including eye pressure and eye movement tests). * Participants with healthy eyes will participate in eye movement testing experiments: * One or more sessions lasting less than three hours each. * Eye movements will be recorded with a video/infrared camera system. * For the majority of the studies done under this protocol, only one or two sessions will be required. A few studies recording very small eye movements will require three or more sessions.