Wiktionary
scotopic
a. (context of vision English) monochromatic, as used in near darkness, using the rod cells
WordNet
Wikipedia
Usage examples of "scotopic".
The rods, on the other hand, can be stimulated by much lower levels of light than the cones can and are therefore involved in scotopic (skoh-top'ik.
He has a double Purkinje shift with maximum scotopic vision occurring in both the yellow and the blue-violet ranges.