The Effects Of Nearpoint Stress On Horizontal Fixation Disparity Under Open Loop Conditions.

Fixation disparity measurements at near continue to become increasingly useful for prescribing near point lenses, visual therapy, and prism, as well as identifying binocular anomalies. The intent of this study was to evaluate the effects of nearpoint reading stress on one's fixation disparity curve under conditions where accommodation or convergence were virtually eliminated. Visually the curves tended to be steeper with increased exo fixation disparity toward the base out side following reading monocularly to open the vergence loop. The poststress curves following reading through multiple pinholes binocularly were not as significant, but tended to become more eso with base out prism and the central portion of the curve generally flattened with a decrease in measured fixation disparity.