Mesopic luminous-efficiency functions for various adapting levels.
The luminous-efficiency functions for a centrally viewed 10 degrees field were measured by heterochromatic brightness matching for various retinal illuminance levels of a reference field at various adapting levels. The subject was always presented with a 45 degrees white adapting light except when the test field for brightness matching was substituted for the adapting field for 500 msec. In order to investigate the contributions of rods and cones to the brightness sensation, the luminous-efficiency curves obtained from two subjects were analyzed with the Ikeda-Shimozono formula. When the subject was presented with an adapting light above about 100 trolands (Td), the luminous-efficiency function became photopic at any luminance level of the test field; similarly, when the test field was at 100 Td, the luminous-efficiency function was photopic at any adapting level.
D000221:Adaptation, Ocular; D000328:Adult; D006801:Humans; D008027:Light; D008297:Male; D010775:Photic Stimulation / Q000295:instrumentation / Q000379:methods; D010786:Photoreceptor Cells / Q000502:physiology*; D014785:Vision, Ocular / Q000502:physiology*