The pupillometric precision of a remote video eye tracker

To determine the accuracy and precision of pupil measurements made with the Tobii 1750 remote video eye tracker, we performed a formal metrological study with respect to a calibrated reference instrument, a medical pupillometer. We found that the eye tracker measures mean binocular pupil diameter with precision 0.10 mm and mean binocular pupil dilations with precision 0.15 mm.