Abstract

The effect on foveal dark adaptation of pre-exposure of the eye for brief durations to light of relatively low brightnesses was investigated after the eye was adapted to different levels of brightness. Monocular measurements of absolute brightness sensitivity were made using a square, one degree on a side, centrally fixated, test patch. The course of dark adaptation as measured by the RL was investigated following ten minutes exposure to each of three adaptation levels, 0.10, 1.0, and 10. ft-L. In addition, the effect of superimposing certain combinations of pre-exposure brightnesses (100., 10., and 1.0 ft-L) and durations (100, 10, and 1 sec) upon each of the adaptation levels was investigated. The effect of increasing adaptation level, in the absence of pre-exposure, was to increase the loss of sensitivity, and hence the extent of subsequent dark adaptation. The effects of superimposing various pre-exposures upon the different adaptation levels were found to be complex. With two exceptions, the only instances in which pre-exposure superimposed upon adaptation level produces more subsequent adaptation than adaptation level alone occurred when the product of pre-exposure brightness and duration exceeded 100 ft-L-seconds. Occasional combinations of pre-exposure brightness and duration superimposed upon an adaptation level appeared to produce no subsequent adaptation which could be measured with the apparatus and technique used.

© 1956 Optical Society of America

Studies on Dark Adaptation. I. The Pre-Exposure Tolerance of the Dark-Adapted Fovea*

Dorothea E. Johannsen, Patricia I. McBride, and Joseph W. Wulfeck
J. Opt. Soc. Am. 46(1) 67-71 (1956)

Studies on Dark Adaptation. III. Pre-Exposure Tolerance of the Human Fovea as Measured by Contrast Sensitivity*†

Joseph W. Wulfeck, Dorothea E. Johannsen, and Patricia I. McBride
J. Opt. Soc. Am. 50(6) 556-558 (1960)

Studies on Dark Adaptation. IV. Pre-Exposure Tolerance of the Dark-Adapted Peripheral Retina*

John A. Hanson, Joseph W. Wulfeck, and Edythe M. S. Anderson
J. Opt. Soc. Am. 50(6) 559-561 (1960)

Studies on Dark Adaptation. V. Effect of Various Sizes of Centrally Fixated Pre-Exposure Fields on Foveal and Peripheral Dark Adaptation*

John A. Hanson, Edythe M. S. Anderson, and Richard P. Winterberg
J. Opt. Soc. Am. 50(9) 895-899 (1960)

Studies on Dark Adaptation. VII. Effect of Pre-Exposure Color on Foveal Dark Adaptation*

John A. Hanson and Edythe M. S. Anderson
J. Opt. Soc. Am. 50(10) 965-969 (1960)