Abstract
Using the method of electrostimulation the relation between the electrical excitability of the eye and the duration of illuminating white light was studied at 20° from the foveal center.
The percentage increase in electrical excitability following an illumina-tion was expressed by ζ. ζ-time curves consist of three elevations situated at 1.5 and 3 seconds from the end of illumination and at 4.5 seconds from its onset. The latter was designated “a rod process”, while the process with its crest at 1.5 sec. and that at 3 sec. were described as Y- and B-processes respectively.
1. The magnitudes of the Y-process increased in proportion to the logarithms of the durations of illumination, and at a certain critical duration they became saturated. These critical duration was called “saturation time”. When the intensities of illumination were increased to 100 lux and above, the saturation time was always 0.5 seconds. This coincides precisely with that found by Oba at the fovea.
2. The saturation times at such lower intensities as 0.1, 1 and 10 lux were always 6 sec., and in the intermediate region from 100 to 10 lux the value of saturation time varied from 6 to 0.5 seconds.
3. With the B-process quite the same result was obtained as with the Y-process.
4. The data were interpreted in terms of photopic and scotopic excitation of the retina.
I am greatly indebted to Prof. K. Motokawa for his many valuable dis-cussions and kind guidance.
