1. A method of detecting, and classifying severity of, a retinal disease using retinal images, comprising: at least one of receiving, retrieving or generating reference data comprising information concerning occurrences of key image features for each of a plurality of retinal disease and disease severity conditions; receiving a retinal image of an individual; processing said retinal image of said individual to identify occurrences of each of a plurality of distinguishable image features throughout at least a region of interest of said retinal image; identifying which ones of said identified occurrences of said plurality of distinguishable image features of said retinal image of said individual correspond to said key image features of said reference data; calculating, based on said identifying, a number of occurrences of each of said key image features in said retinal image of said individual; and determining at least one of a likelihood of a presence of a retinal disease or a likelihood of developing a retinal disease based on a comparison of said number of occurrences of each of said key image features in said retinal image of said individual to said reference data.