A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / Background and Significance: Spectral Domain-Optical Coherence Tomography (OCT) is one of the most widely used imaging modality in Ophthalmology. It utilizes light waves to visualize the various layers of the retina. The OCT machines offer two different scan patterns, the circular and the cube scan patters. It is important to compare these scan pattern to see if any discrepancy exist in quantifying retinal indices. One of the newer indices is the Bruch’s membrane opening minimum rim width (BMO-MRW), which is the minimum distance between from the BMO to the inner limiting membrane (ILM). The BMO-MRW is being used in the diagnosis of glaucoma. Hypothesis: To compare the cube and radial scan patterns of the SD-OCT for quantifying the BMO-MRW. We hypothesis that there might be some differences between the two scan patterns.