A simple pupil-independent method for recording eye movements in rodents using video

Previous techniques using video to acquire torsional eye-movement recordings in humans have needed to control confounding effects associated with dilation of the pupil. A new pupil-independent, three-dimensional eye-movement recording method was developed to overcome the reliance on tracking the pupil by interpolating between two artificial landmarks placed on the eye. This technique reliably quantified torsional changes in angular eye position at variable amplitudes of horizontal and vertical excursion over at least a 20 degrees range. Application of this system to rodents naturally lacking a clearly defined pupil allows behavioral researchers to obtain torsion in addition to horizontal and vertical changes in angular eye position.