To establish baseline, the participants will undergo two separate detailed eye examinations and a single neurology/neuroimaging examination within a one to two week period. Afterwards, they will return to the NEI clinic annually until the last-enrolled participant reaches five years of follow-up. Therefore, this study will require a minimum of five study visits. Follow-up visits will consist of a single detailed eye exam and a single detailed neurology/neuroimaging exam. Participants may be seen at more frequent intervals at the investigators discretion, depending on the clinical and research situation. Participants will be required to submit a blood sample for research, and they will have the option to provide a skin biopsy to facilitate research at a cellular level.