Abstract

Greenstein, Hood and their colleagues have made extensive use of the ”flash-on-flash” technique to study mechanisms of psychophysical threshold elevations in various retinal diseases.^1-2 In the flash-on-flash experiment, a flashed test stimulus of intensity ΔI is superposed on a coincidently flashed, but longer duration background stimulus of intensity I. Test flash increment thresholds as a function of flashed background intensity follow a saturating function rather than Weber’s law, the usual function obtained for increment thresholds on steady backgrounds.

© 1987 Optical Society of America