Abstract: An optically realistic model eye is described. The optically realistic eye model has an optical axis and includes: an anterior replaceable module comprising a model cornea, model iris and model lens rotatably mounted for rotation about said axis, said module being representative of an emmetropic or pathological natural eye; an enclosure located posterior to said module and adapted to enclose a retinal area within which an image of an external object is brought to focus by said module; and a photoactive device movable within said enclosure and retinal area and adapted to detect or reflect a portion of the image for inspection, processing or analysis.