[The ERG recording with high speed scanning of monochromatic stimuli]

Sixteen monochromatic lights with peak wavelengths lying from 400 nm to 700 nm at intervals of 20 nm were adjusted to equal energy. These stimuli were provided in a dark room successively in ascending and descending series from 400 nm to 700 nm were arranged to be continuously sinusoidally flickering. The flickering frequency was changed from 3 Hz to 40 Hz. The spectral responses obtained could be seen and evaluated as a spectral pattern on the oscilloscope rectangular CRT. In both ascending and descending scanning of less than 10 Hz stimulus frequency the spectral response pattern with the low stimulus intensity had maximum amplitude around 500 nm, reflecting the function of the rod system. On the other hand the spectral pattern with the peak response from 540 nm to 580 nm was obtained by the high stimulus intensity, reflecting the function of the cone system. In scanning of more than 20 Hz frequency, the spectral pattern also reflected the characteristics of the cone system. In normal subjects almost the same spectral pattern was obtained at high speed scanning, especially more than 30 Hz for a few seconds, even by averaging. This method can therefore be employed for clinical diagnosis.