Calculating photopic illuminance.
A procedure is proposed for computing the visual effectiveness of light incident on the retina considering the directional sensitivity of the underlying photoreceptor population. A half-sensitivity half-width measurement of the retinal directional sensitivity provides the basis for integrating a parabolic approximation to the directional sensitivity over the pupillary area penetrated by the incident light.
D006801:Humans; D008027:Light; D055095:Optics and Photonics; D009907:Optometry / Q000295:instrumentation / Q000379:methods; D012160:Retina / Q000502:physiology*; D014785:Vision, Ocular / Q000502:physiology*