Scotopic vision Scotopic vision Scotopic vision is the vision of the eye under low-light levels. The term comes from Greek "skotos", meaning "darkness", and "-opia", meaning "a condition of sight". In the human eye, cone cells are nonfunctional in low visible light. Scotopic vision is produced exclusively through rod cells, which are most sensitive to wavelengths of around 498 nm (green–blue) and are insensitive to wavelengths longer than about 640 nm (red). This condition is called the Purkinje effect. Scotopic vision is dominated by retina amacrine cells, specifically AII-amacrine cells. AII-amacrine cells capture rod bipolar cell input and redistribute it to cone
Light therapy is using blue light with aminolevulinic acid for the treatment of actinic keratosis. This is not a U.S. FDA-approved treatment for acne vulgaris. The production of the hormone melatonin, a sleep regulator, is inhibited by light and permitted by darkness as registered by photosensitive ganglion cells in the retina. To some degree, the reverse is true for serotonin, which has been linked to mood disorders. Hence, for the purpose of manipulating melatonin levels or timing, light boxes providing very specific types of artificial illumination to the retina of the eye are effective. Light therapy uses either a light box which