A system is described for obtaining standardized photographs of the iris with exposure dependent on iris color. Analysis of iris color of these photographs uses image analysis digitized in the red-green-blue spectrum for determining changes of iris color over time in patients with disease and on drug therapy. A region of interest of the iris is selected to minimize artifacts such as corneal reflection. White light (Red-Green-Blue) spectrum or color ratios such as red/blue are used to measure density and areas of color over at selected time intervals. The image analysis digitized in the red-green-blue spectrum for measuring color of iris photographs show no significant change in iris color in normals, but did show significant changes in iris color in glaucomatous eyes treated with precription eye drops.