 Each subject will be enrolled by his or her written informed consent obtained by members of the study staff. Following an initial telephone screening, each prospective subject will undergo an in-depth psychological evaluation at BWH by the principal investigator, Janis L. Anderson, PhD., or at McLean Hospital by Carol Glod, RN, Ph.D. Prior to the psychological screening, Dr. Anderson or Dr. Glod will review the Screening Consent Form with the subject. Dr. Anderson is an experienced clinical psychologist and Dr. Glod is an experienced doctor of nursing; each is trained to consider both cognitive and emotional factors that affect the ability to consent. If written informed consent is obtained on the Screening Consent Form then the psychological evaluation will take place. In that evaluation meeting, Dr. Anderson or Dr. Glod also will present the subject with a copy of the Study Consent Form to review and take home. Subjects will be encouraged to inform their medical providers and therapists about their interest in participating in the study. The meetings with Dr. Anderson or Dr. Glod will be scheduled in advance; nothing in the circumstances of this protocol would require a hasty decision on the part of the potential subject. Subsequent to the psychological screening for prospective subjects who meet diagnostic criteria, a medical examination will be performed by a doctor of Ophthalmology. If the subject is found to meet all inclusion criteria for the study, doctor of Ophthalmology, a licensed physician, will review the Study Consent Form and obtain written informed consent for the study procedures themselves. Upon each outpatient visit for the study procedures, the subjects mental status will be reassessed. However, due to the nature of SAD symptoms and the inclusionexclusion criteria for the present study, we do not anticipate enrolling subjects whose ability to consent would be transitory. 