Monocular and binocular abutting line vernier acuities were measured as a function of contrast. Over a range of contrasts from near the line-detection threshold to approximately 20 times threshold, binocular vernier thresholds are lower (better) than monocular thresholds by approximately 50–60%, similar to the binocular improvement found for the detection of both a thin line and a dipole. At higher contrasts the binocular advantage diminishes, apparently as a result of saturation.
© 1991 Optical Society of America
Original Manuscript: August 3, 1990
Manuscript Accepted: November 27, 1990
Published: April 1, 1991
Tom Banton and Dennis M. Levi, "Binocular summation in vernier acuity," J. Opt. Soc. Am. A 8, 673-680 (1991)