Accession Number : AD0710003

Title :   THE EFFECT OF FOCUSING ON VISUAL THRESHOLDS WHEN THE UNIT OF MEASUREMENT IS FLUX DENSITY.

Descriptive Note : Final rept.,

Corporate Author : FORDHAM UNIV BRONX N Y

Personal Author(s) : Zegers,Richard T.

Report Date : 1965

Pagination or Media Count : 21

Abstract : Determinations of shifts in the visual threshold energy values as a function of target focus were determined for five focusing positions for two subjects. The ascending method of limits was employed. Fifty judgments per wavelength were obtained at each focus position for each subject. Subject 1 was tested on seven 5 nm band of monochromatic light between 420 and 600 nm. Subject 2 was tested on 13 wavelengths between 440 and 700 nm. Results showed that, under the conditions of this experiment, the threshold varies as an increasing linear function of the position of the diaphragm from the position nearest the subject's eye to that farthest from him. The amount of change is also a function of the wavelength of the stimulus with slope values generally decreasing with increasing wavelength. These data point to the importance of accurate focusing as a factor in visual experimentation when flux density measurements are employed. (Author)

Descriptors :   (*VISUAL PERCEPTION, THRESHOLDS(PHYSIOLOGY)), COLORIMETRY, EYE, FOCUSING, COLORS, SENSITIVITY, STATISTICAL ANALYSIS, CURVE FITTING

Subject Categories : Anatomy and Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE