Disclosed embodiments include a method for retinal image analysis implemented in a medical system with one or more processors comprising the method steps of: (a) locating an optical disk on the retinal images and establishing a plurality of circumferences centered at the disk; (b) detecting a plurality of vessels within a region defined by said circumferences' radii using a crease-based algorithm; (c) extracting a plurality of vessel segments based on a deformable models (snakes) algorithm; (d) measuring a plurality of vessel calibers; (e) classifying each vessel as a vein and an artery; and (f) computing an arteriolar-to-venular ratio.