To describe and establish control data from controls for a simultaneous interocular brightness sense test in which the apparent brightness of two independently viewed light patches was compared.
Dichoptic viewing was achieved by dissociation of right and left eyes using a septum and crosspolarization. Brightness matches were obtained by using adjustments to the illumination of the left retina while the illumination of the right retina was kept constant.
Ninety-one control observers (age range, 20 to 91 years) participated in the study to provide normal brightness-matching data.
Effects from ocular dominance, age, and long- and short-term adaptation were negligible, but the test was sensitive to anisocoria. Just noticeable differences in dichoptic brightness matching were proportional to retinal illuminance; this finding was consistent with the Weber-Fechner law.
The test is quick and simple to complete and appears to offer considerable scope for the assessment of visual function when differences in the functional integrity of the optic nerves of the right and left eyes are suspected.
MacMillan ES, Cummins D, Heron G, Dutton GN. The Simultaneous Interocular Brightness Sense TestA Test of Optic Nerve Function. Arch Ophthalmol. 1994;112(9):1190-1197. doi:10.1001/archopht.1994.01090210074019