1. A method comprising: receiving three-dimensional data representative of a plurality of layers of a retina of a subject under test; determining, from the received data, oxygen concentration at one or more of the plurality of layers; detecting, based on the determined oxygen concentration, a region of at least one a high oxygen concentration in the retina or a low oxygen concentration in the retina; and comparing the detected region to reference data to determine whether the retina including the detected region suffers from or will suffer from at least one of a retinal disease or a degeneration of the retina, wherein the receiving, the determining, the detecting, and the comparing are performed by at least one processor.