ABSTRACT The invention is directed to methods of detecting and/or measuring a feature in a retinal mage. The feature detected and/or measured may be one or more of the optic disc, optic disc centre, optic disc radius, vessel edge, vessel calibre/width and vessel central reflex. One method for detecting the optic disc includes analyzing an image histogram to determine intensity levels analyzing the intensity levels to determine a threshold intensity for potential optic disc regions determining the number of pixels for each potential optic disc region and calculating the centre of each potential optic disc region from the number of pixels in each potential optic disc region to thereby detect the optic disc.
