The integrating power of the eye has been tested for short flashes of light, ranging in duration from 10<sup>-2</sup> to 8 × 10<sup>-9</sup> 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)