Stereoscopic acuities were determined with and without eye movement, following the experimental procedure used by Wright. Two illuminated apertures were used as the targets seen in the dark against a black background. Measurements were made for these targets separated horizontally for various visual angles up to 52 degrees and for high, low, and unequal luminances. A critical study of the results showed that disparity was responsible for the greater part of stereoscopic acuity. The part played by eye movement (convergence movements), if any, appears to be constant and is of minor importance compared to the part played by disparity.
A. A. RADY and I. G. H. ISHAK, "Relative Contributions of Disparity and Convergence to Stereoscopic Acuity," J. Opt. Soc. Am. 45, 530-534 (1955)