The Site of Electrical Excitation of the Human Eyes by the Sinusoidal Alternating Currents at Frequency of 20 CPS
1958 年 67 巻 2-3 号 p. 163-172
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1958 年 67 巻 2-3 号 p. 163-172
Taking, as an index of excitation of the eyes, flickering sensation (electrical phosphenes) elicited by the sinusoidal alternating currents at 20 cps. passing through the head, the author studied precisely the relation of electric threshold of the eye to radiance of the adapting light of different wavelengths.
1. The electric threshold strength-log-radiance curve has a reversed S-shape. The course of the curve can be divided into three sections, each corresponding to three physiologically significant states of vision, that is, scotopia, mesopia and photopia.
2. The electrical excitability-wavelength curve for equal energy spectrum resembles greatly the scotopic luminosity curve in form.
As to the position of the crest on this curve, no shift takes place toward longer wavelength such as Purkinje shift even when the radiance of the adapting light is raised sufficiently.
3. Decrease in electric threshold of the eye for 20 cps. due to illumination with monochromatic rays is always accompanied with increase in saturation of the color, except for red. Both kinds of variations take place only within a relatively narrow mesopic range of illumination, where both rods and cones are in action concurrently.
4. These results support Mita et al's view that the structures stimulated by the currents at 20 cps. may be bipolar cells.
