Lau optometer: A new subjective instrument to measure the astigmatism of the human eye

Abstract

We have developed an optometer to measure the ocular astigmatism of human eyes and tested its performance. In this instrument we make use of an optical field that has coherence only along specific meridians to form interference images of different orientations on the subject's retina. The subject sees fringes of different orientations sequentially, at a fixed vergence, by rotating an eyepiece consisting of a probe cylinder. From the angular positions of the eyepiece at which each of the fringes are seen best by the subject, his or her astigmatism is calculated. The instrument has the potential to probe meridional vision and accommodation characteristics of human eyes.