Eye-tracking infra-red optometer

An eye-tracking infra-red optometer has been developed to measure dynamic refractive power during slow horizontal eye movement. It consists of two instruments: an optometer to measure the refractive power of the human eye, and an eye tracker. When measuring refractive power, the eye tracker is used to maintain automatically the optical axis of the optometer coincident with the visual axis of the human eye. The measurement range of the optometer is approximately -10 to + 10 D; refractive power is measured with an accuracy of about 0.4 D and with a precision of 0.05 D over an eye movement range of 60 degrees. The maximum trackable eye movement velocity is over 100 degs-1, with a time delay of about 0.13 s. Furthermore it was confirmed that eye refraction measurement during vergence is possible using this eye-tracking infra-red optometer.