1 ) A method for quantifying a blood vessel reflection parameter associated with a biological subject, the method including, in at least one electronic processing device: a) determining, from a fundus image of an eye of the subject, edge points of at least one blood vessel in a region near an optic disc; b) processing the fundus image, at least in part using the edge points, to identify blood vessel edges and central reflex edges; c) determining blood vessel and central reflex parameter values using the blood vessel edges; and, d) determining a blood vessel reflection parameter value at least partially indicative of blood vessel reflection using the blood vessel and central reflex parameter values.