OCT enables tissue pathology to be imaged in situ and in real time with a resolution approaching that of conventional histopathology but without the need for excising and processing specimens. OCT provides a quantitative method of directly measuring ocular structures with high precision and could provide an objective, early diagnosis for glaucoma, age related macular degeneration (ARMD), diabetic retinopathy, macular edema, and other pathologies. Extensive studies have been performed with OCT in cross-sectional as well as longitudinal setting. In this ongoing protocol, our objective is to continue these studies using the commercial ophthalmic OCT imaging instruments to develop methods for early detection and improve longitudinal assessment for the above mentioned ocular pathologies.