DURING the naval battles of World War I, mistakes were made in discrimination of position and direction of movement of a formation of ships. To the lookout the ships appeared to be moving in a straight line, when in reality they were moving obliquely in step formation. Such an error in perception would be typical of anisopia or anisodominance. The anomalies apply especially to aircraft formation flying and landing operations but also to automobile traffic situations, where target and background contrast is unusually high.
Anisopia is an anomaly, discovered by Cibis,1 which may exist from a monocular defect in the brightness or in the focus of one retinal image. It results in an apparent rotation, or "venetian-blind effect," of contrasting surfaces in a frontal plane on their individual central vertical axes. When the phenomenon is elicited in a normal person by reducing the light striking one retina, it may
MILES PW. ANOMALOUS BINOCULAR DEPTH PERCEPTION DUE TO UNEQUAL IMAGE BRIGHTNESS. AMA Arch Ophthalmol. 1953;50(4):475-478. doi:10.1001/archopht.1953.00920030483008