Background data including age, sex, medical history, and neurologic history and status will be gathered prior to the study/OCT testing visit. At the single study/testing visit, subjects will have their blood pressure and intraocular pressure checked (using numbing drops that last 15-20 minutes), undergo vision testing and then have their eyes dilated with standard dilating drops. They will then undergo optical coherence tomography testing to determine the blood flow of the retinal blood vessels and to take other measurements of the back of the eye including thicknesses of the nervous tissue elements of the retina.
OCT Procedure: The subject will be seated and have their head positioned on a chin rest. They will be asked to look at a target (a lighted spot) while a beam of light scans the front part of the eye. The light is infrared and will not be visible or cause any sensation. A cotton tip swab may be used to help hold the eyelid open temporarily if necessary.