title: Spectral luminous-efficiency functions obtained by direct heterochromatic brightness matching for point sources and for 2 degrees and 10 degrees fields.
abstract: Brightness luminous-efficiency functions for point sources and for 2 degrees and 10 degrees fields are based on 6, 63, and 76 subjects, respectively. The function for point sources can be approximated by Judd's 1951 modification of the CIE V(lambda) function. The 2 degrees and 10 degrees functions differ greatly from V(lambda). The two functions differ from each other only at wavelengths from 410 through 520 nm, where the differences are attributed to absorption by the macular pigment.
mesh_terms: D006801:Humans; D008027:Light; D011601:Psychophysics; D014796:Visual Perception / Q000502:physiology*