Open AccessDirectional light-capture efficiency of the foveal and parafoveal photoreceptors at different luminance levels: an experimental and analytical study
Author(s) -
Alessandra Carmichael Martins,
Brian Vohnsen
Publication year - 2019
Publication title -
biomedical optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.362
H-Index - 86
ISSN - 2156-7085
DOI - 10.1364/boe.10.003760
Subject(s) - photopic vision , foveal , mesopic vision , optics , retinal , luminance , retina , wavelength , physics , flicker , visible spectrum , directionality , eccentricity (behavior) , brightness , materials science , chemistry , computer science , biology , biochemistry , operating system , law , political science , genetics
A gradual drop in visibility with obliquely incident light on retinal photoreceptors is namely described by the Stiles-Crawford effect of the first kind and characterized by a directionality parameter. Using a digital micromirror device in a uniaxial flicker system, here we report on variations of this effect with luminance levels, wavelengths within the visible and near-infrared spectrum and retinal regions ranging from the fovea to 7.5° parafoveal. Results show a consistent directionality in mesopic and photopic conditions. Higher directionality is measured for longer wavelengths, and a decrease with retinal eccentricity is observed. Results are discussed in relation to an absorption model for the visual pigments taking the outer-segment packing and thickness of the neural retina into account. Good correspondence is found without enforcing photoreceptor waveguiding.