Photopic and scotopic flicker sensitivity of a rod monochromat

The sensitivity to sine-wave flicker of a rod monochromat was compared with that of a normal subject at photopic and scotopic levels of luminance. The sensitivity of the rod monochromat in the low-frequency region (below 3 Hz at scotopic levels and below 12 to 14 Hz at photopic levels) was found to be superior to that of the control. This superiority was most pronounced at photopic levels, where the rod monochromat frequently showed a two-peak sensitivity curve.