In the study of visual perception, scotopic vision (or scotopia) is the vision of the eye under low-light conditions.[1] The term comes from the Greek skotos, meaning 'darkness', and -opia, meaning 'a condition of sight'.[2] 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 and are insensitive to wavelengths longer than about 640 nm.[3] Under scotopic conditions, light incident on the retina is not encoded in terms of the spectral power distribution. Higher visual perception occurs under scotopic vision as it does under photopic vision.[4]
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