Stereopsis angle in relation to proximity and induced refractive errors

Dependence of stereoacuity (SA) angle on the reciprocal of the test distance with positive, negative, and zero values of induced refractive errors is demonstrated with the three-rod test and the mean errors statistical method. Two male emmetropes and one hyperope showed linearly increasing dependence of SA angle on the reciprocal of the test distance within the subject's range of clear vision extended at both ends by 1 D. Linear regression coefficients were not influenced by the value of induced refractive error within +/- 2 D. Correlation coefficients in the case of corrected refractive error were about 0.90, but their mean value in the case of induced refractive errors was 0.83.