The simultaneous interocular brightness sense test. A test of optic nerve function.
OBJECTIVE
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.


METHODS
Dichoptic viewing was achieved by dissociation of right and left eyes using a septum and cross-polarization. Brightness matches were obtained by using adjustments to the illumination of the left retina while the illumination of the right retina was kept constant. OBSERVERS: Ninety-one control observers (age range, 20 to 91 years) participated in the study to provide normal brightness-matching data.


RESULTS
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.


CONCLUSIONS
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
E S
ES
Department of Vision Sciences, Glasgow Caledonian University, Scotland.
Cummins
D
D
Heron
G
G
Dutton
G N
GN
D000221:Adaptation, Ocular / Q000502:physiology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015875:Anisocoria / Q000139:chemically induced / Q000503:physiopathology; D004292:Dominance, Cerebral / Q000502:physiology; D006801:Humans; D008875:Middle Aged; D009900:Optic Nerve / Q000502:physiology*; D010775:Photic Stimulation; D015203:Reproducibility of Results; D012684:Sensory Thresholds / Q000502:physiology; D014331:Tropicamide; D014787:Vision Tests / Q000379:methods*; D015348:Vision, Binocular; D014796:Visual Perception / Q000502:physiology*
D014331:Tropicamide