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 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 .