Binocular infrared optometer for measuring accommodation in both eyes simultaneously in natural-viewing conditions

A binocular IR optometer has been developed to measure accommodation continuously and simultaneously in both human eyes in conditions close to natural viewing where a subject gazes at an actual target with binocular vision. Measurement accuracy is ~ 0.24 D with a precision of 0.05 D within a refractive-power range of + 10 to -10 D in model eyes. The dynamic response is over 100 D/s. In addition we measured simultaneously and continuously accommodation, pupil diameter, and eye position of both human eyes in near-reflex conditons using this binocular optometer. Development of the tracking IR binocular optometer is discussed in detail.