Growing evidence shows that altered blood flow plays a major role in many vision-threatening diseases including glaucoma, diabetic retinopathy, age-related macular degeneration, Central Retinal Vein Occlusion, and Branch Retinal Vein Occlusion. Optical coherence tomography, an established imaging technique use for eye exam in clinical ophthalmology, provides high-resolution cross sectional images of the retina and has increased our ability to understand many eye diseases.