Patent ID: 7673991

Claim:
Method of measuring the retinal stray light in the eye of a subject, comprising: presenting to the subject a flickering stray light from a stray light source positioned at a predefined angular distance from a test area, a part of the flickering stray light being imaged on the retina at a location corresponding to the location of the test area; presenting to the subject compensation light from a compensation light source arranged at a position in the test area, the parameters of the compensation light being set so as to undercompensate said part of the flickering stray light being imaged on the retina at the location corresponding to the location of the test area; presenting to the subject compensation light from a compensation light source arranged at a position in the test area, the parameters of the compensation light being set so as to overcompensate said part of the flickering light being imaged on the retina at the location corresponding to the location of the test area; receiving an input signal representative of the result of a comparison between the resulting retinal light flickering as perceived by the subject for the undercompensated test area and the resulting retinal flicker intensity for the overcompensated test area; varying the value(s) of one or more of said parameters defining one or more of the stray light source light and the compensation light source light; repeating the above steps for different parameter values; determining, using the received input signals and the corresponding parameter values of the stray light source and the compensation light sources, those parameter values wherein the perceived retinal light intensities of the undercompensated and overcompensated test area are substantially equal; and calculating from the determined parameter values a stray light parameter representative of the retinal stray light induced by the stray light source.