A comparison in photopic and melanopic spectral sensitivity. The photopic response is our visual response to light (rods and cones) whereas the melanopic sensitivity is the non-visual response to light, resulting in light entrainment of our circadian rhythm. (A) shows the comparison of both spectral sensitivity to D65 daylight, a daylight standard set by the International Commission on Illumination (CIE). It shows that the melanopic spectral sensitivity has a closer match to daylight. (B) shows both spectra multiplied with similar irradiance of 1000 lux [21].