Patients with diabetic retinopathy, age-related macular degeneration, vascular occlusive disease, central serous retinopathy or another retinal disease may be eligible for this study. Candidates will be screened with a medical history, brief physical examination, thorough eye examination and blood test. The eye examination includes measurements of eye pressure and visual acuity (ability to see the vision chart), examination of the pupils and eye movements, and dilation of the pupils to examine the lens and retina. Patients will also undergo fundus photography and fluorescein angiography, as follows: