VISUAL RECOVERY FROM HIGH INTENSITY FLASHES
Interim rept. no. 1, 15 May 1964-15 May 1965
OHIO STATE UNIV RESEARCH FOUNDATION COLUMBUS
Pagination or Media Count:
High intensity flashes of 0.04 msec to 1.4 msec duration were used to determine the afterimage brightness as a function of time following the flash. Six human subjects made continuous matches of the afterimage for periods up to six minutes following the flashes. The flash energies ranged from 3 x 10 to the minus 7th power to 800,000 td.sec or from 0.012 to 0.0003 calcm sq. at the retina, neglecting losses in the ocular media. The mean afterimage brightness, 5 sec following the highest intensity flashes, was 100,000 td. The afterimage brightness data were correlated with recovery time measurements for Sloan - Snellen letters presented at luminance levels from 280 mL to 0.07 mL. The reciprocity relationship between the duration and luminance of flashes subtending 7.5 degrees visual angle was investigated for constant flash energy of 3 x 10 to the minus 7th power td.sec. Seven flash durations from 0.5 to 5.0 msec were tested. The recovery times for the Sloan-Snellen letters at various luminance levels increased approximately 30 following 1.5 msec flashes compared with the 0.5 msec flashes. There was no apparent change for the mean recovery times for four subjects following flashes from 1.5 msec in duration.
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