1. A method for diagnosing medical conditions having retinal manifestations, comprising the steps of: providing a CBIR system including an archive of stored digital retinal photography images and diagnosed patient data corresponding to said retinal photography images, said stored images each indexed in a CBIR database using a plurality of feature vectors, said feature vectors corresponding to distinct descriptive characteristics of said stored images; obtaining a query image of the retina of a patient; identify using image processing regions or structures in said query image; describing said regions or structures using said plurality of feature vectors; retrieving at least one relevant stored image from said database based on similarity to said regions or structures, and diagnosing a disease having retinal manifestations in said patient based on said diagnosed patient data associated with said relevant stored image.