Refraction measurements with an open-view binocular Shack-Hartmann wavefront sensor

Abstract

We have developed an open-view binocular Shack Hartmann wavefront sensor to measure accommodation, vergence, pupil size, and monochromatic aberrations of both eyes. Two optical channels, comprised of Shack-Hartmann wavefront sensors and anterior imaging cameras, were laterally aligned to both eyes. A dichroic mirror reflected near infrared light between the eye and the measuring instrument while visible light from an object passed thorough the mirror to the eye. We used one million pixel CCD cameras and three fast PCs to grab images from the sensors and analyze data. We confirmed the accuracy and precision of the refraction using model eyes and human eyes. We measured refraction of 50 eyes in 25 normal subjects using the wavefront sensor and a commercial autorefractometer. Accuracy of refraction was found to be 0.03 diopters when we measured the model eyes. The precision was less than 0.18 diopters for human eyes. Correlation coefficients of determination between the wavefront sensor and commercial autorefractometer were 0.96 for both eyes. We believe the open-view-binocular wavefront sensor will be a useful instrument for the investigation of the refraction and accommodation under natural viewing condition.

Footnotes

 This research was supported by “strategic information and communications R&D promotion scheme” from the Japanese Ministry of Internal Affairs and Communications.