Monocular Adaptation Research Articles

Orientation specific colour adaptation at a binocular site.

MCCOLLOUGH1 found that after alternate viewing of vertically oriented red gratings and horizontally oriented blue gratings, achromatic gratings appear tinted blue when oriented vertically and pink when oriented horizontally. This indicates the existence of colour specific edge detectors in the visual system. Further, since interocular transfer of the effect was not possible, McCollough concluded that no binocular cells are involved in this type of adaptation. This view has been supported by many investigators2–5 who used different paradigms. But their failure to illustrate orientation-contingent colour adaptation at a binocular locus may be attributable to the fact that most of their experimental situations, like McCollough's, did not provide the ideal stimulus for binocular neurones, which respond best, showing “binocular synergy”, only when the stimulus is simultaneously presented to both eyes6–9. I have attempted optimal excitation of the binocular cells by alternately presenting red vertical and blue horizontal gratings to both eyes and isolating adaptation of binocular neurones by cancelling monocular adaptation with presentation of a pair of complementary gratings (blue vertical and red horizontal) to each eye separately for an equal length of time. The results of this procedure show that adaptation does involve binocular neurones.

Effectiveness of red light on dark adaptation.

Some studies of 1941–1942 indicated that adaptation under red light was faster than in darkness. A recent (May 26, 1952) research report originating from the Naval Air Station at Pensacola seems to show a facilitative effect of red light on dark adaptation and has renewed interest in this problem. Some of the earlier data purporting to show this effect, additional material previously unpublished, and also new studies made at Yale by the method of simultaneous differential monocular adaptation are here presented and discussed. Adaptation goggles were used for 25 min under illumination of 8 mL. The filter over one eye was a glass disk made of Corning No. 2403, deep red, 3.5 percent photopic transmission, over the other eye an opaque cardboard disk which excluded all light. Dark-adaptation thresholds (Hecht-Schlaer adaptometer) violet light (Corning 5513), measured alternately on the two eyes showed for 16 college student subjects lower values, i.e., increased light sensitiveness for the eyes adapted in darkness. In the period 6 min after removing the goggles the mean threshold difference between results for red and opaque procedures in the first test was −0.153 log μμL, <P=0.01; in the second test with the goggles reversed on the two eyes the mean difference favoring the opaque side was −0.182 log I, μμL, <P=0.01. The earlier and later results are not easily harmonized. The author argues in favor of the monocular method as an appropriate one for the study of this problem.