The integrating power of the eye has been tested for short
flashes of light, ranging in duration from 10-2 to 8 × 10-9 sec.
The shorter flashes were produced by passing the image of the
straight filament of an electric lamp across a narrow slit, the
light having been reflected from a mirror mounted on an air-
driven turbine. The longer flashes were produced by means of a
sectored disk. In all cases the number of flashes received by
the eye was great enought to avoid flicker and the intensity was
well above that required to produce the sensation of vision. It
was concluded that the response of the eye depends only upon the
total amount of light in the beam and is independent of the
length of the light flash. The limit of error was 1.5 percent.
THOMAS E. GILMER, "The Integrating Power of the Eye for Short
Flashes of Light," J. Opt. Soc. Am. 27, 386-386 (1937)