The limbus reflection method for measuring eye position

Abstract

Eye position can be measured by reflecting light off the iris-scleral limbus. This method provides at least 1/2 deg accuracy over a range of 30 deg horizontally and 20 deg vertically. The limbus reflection method usually requires that the subject's head be held rigid by a bite plate. The method offers the advantages of costing less than most other techniques and of conveniently interfacing with a laboratory computer for automated data reduction. Limbus reflection sensors have been constructed at over a dozen different laboratories, and one apparatus is available commercially. Not all implementations have reached the attainable accuracy and range, especially for eye movements in the vertical direction. © 1975 Psychonomic Society, Inc.