VISUAL PERFORMANCE FOLLOWING HIGH INTENSITY FLASHES
Rept. no. 3 (Final), 16 May 1966-15 May 1967
OHIO STATE UNIV RESEARCH FOUNDATION COLUMBUS
Pagination or Media Count:
Three separate investigations into various areas of visual function at high levels of adaptation are reported. The reciprocity relationship between duration and intensity was studied for flashes of the order of 10 to the 7th power td.sec and for durations of 1.2 msec and 1.5 sec. There was approximately a 40 increase in recovery times for Sloan-Snellen test letters following the longer flashes. The effect of varying the interval between two 250 millimicron sec flashes on the subsequent recovery times was investigated. The interval between flashes was varied from zero to 1 msec in 100 microsec increments. The total integrated luminous energy in the flashes was of the order of 10 to the 7th power td.sec. There was a statistically significant change in recovery time with the interval between flashes at the 5 level. The 700 microsec interval resulted in an 18 increase in recovery compared with the zero interval for 630 mL targets. This is equivalent to more than doubling the energy in the zero interval or 500 microsec duration case. In the third portion of the work, increment thresholds were measured for 45 monochromatic flashes superimposed on a 10 degree white light background of various illuminance levels from 10 td to 50,000 td. At the higher levels, marked notches appear in the sensitivity function at 570 millimicrons and 470 millimicrons as previously reported by Sperling. Analysis of the results show a striking similarity with the purity threshold curve and with MacAdams ellipse for the white point of the chromaticity diagram.
- Anatomy and Physiology