Fig. 3. Continuous line is CIE (Commission International de l'Eclairage) scotopic luminosity curve (rod spectral sensitivity function) derived from psychophysical measurements and placed at a level for normal human subjects; dashed line is Wald's photopic luminosity curve (spectral sensitivity function for the cone mechanisms under photopic conditions) derived from psychophysical measurements of peripheral retinal function. Electroretinographic spectral sensitivity curves for normal rod and cone systems also respectively approximate the solid line and dashed line curves. (Berson EL: Electrical phenomena in the retina. In Hart WM, ed: Adler's Physiology of the Eye. Clinical Application, 9th ed, p 641. St. Louis, CV Mosby, 1992)