A simple continuously recording infrared optometer

The design of a continuously recording infrared optometer for measuring dynamic changes in ocular accommodation is described. The optometer operates on the Scheiner principle, provides a good signal-to-noise ratio, and has several practical advantages over other optometers described in vision literature. It is primarily designed for use in animal experimentation but can be used for humans if eye and pupil movements are controlled. The design of a schematic eye for assessing the dynamic response of the optometer is also presented. Several methods of calibrating the optometer in absolute units are discussed.