1. A method for quantifying disease progression through retinal health assessment and management comprising: obtaining a first image of a retina or iris at a point in time; generating a first vascular map of the first image of the retina or the iris; obtaining a second image of the retina or the iris at a later point in time; generating a second vascular map of the second image of the retina or the iris; registering the first image and the second image on the basis of the first vascular map and the second vascular map; and displaying at least one difference between the registered first image and the second image to quantify a disease progression.