US Patent 7083280 Pupil measuring apparatus

A pupil measuring apparatus includes a mark placed in a space where a background is observable by both eyes; a mark moving device for moving the mark between the eyes and the background; an illumination optical system for illuminating the eyes from the background side; two cameras for respectively imaging the pupils of the eyes; a calculating means for calculating areas or diameters of the respective pupils thus imaged, from video signals of the two cameras; and a display for providing an output of a graph showing change in the areas or diameters of the two pupils calculated against a position of the mark or a time associated with the position on a single screen.