Embodiments of the present invention provide a retinal densitometer, comprising an illumination unit for outputting bleaching illumination for photo-bleaching an eye and reflectance illumination at one or more wavelengths for determining reflectance of the eye at the one or more wavelengths, an imaging device arranged to output image data corresponding to an image of the eye at the one or more wavelengths of reflectance illumination, and a control unit arranged to control the illumination unit and the imaging device to output the bleaching illumination, the reflectance illumination at the one or more wavelengths and to output image data according to a predetermined sequence.
