Photoreceptor directional sensitivity in normals, dichromats and S-cone monochromats

Abstract

The Stiles-Crawford function (SCF) of foveal and 10 peripheral photoreceptors was examined in five normal trichromats, three protanopes, two deuteranopes and two S-cone monochromats on a three-channel Maxwellianview system. The isolating conditions for L-, M-and S-cones were confirmed by heterochromatic flicker photometry. The magnitude of the SCF was found to be concordant with the anatomical variations of the photoreceptors due to receptor type and retinal eccentricity. At the different locations, the SCF was similar in trichromats, dichromats and S-cone monochromats, but varied considerably between observers, regardless of phenotype. Large differences in the number and/or type of functioning cones -as found in normal and colour blind observers -do not seem to influence cone directional properties and as a consequence cone morphology -the SCF being mainly influenced by anatomical changes.

Adaptation of the central retina for high acuity vision: Cones, the fovea and the avascular zone

“…Effectively this means that the pupil is apodized (Atchison et al, 2003; Atchison et al, 2002); that is, the pupil acts like a neutral density filter which increases in density, radially and outwards. The SC apodization is roughly Gaussian in shape, but the part imposed on the pupil is less than ±1 SD (Rynders et al, 1995; Schulze-Dobold et al, 2009), and so does not reduce the effective diameter of the pupil greatly. Nonetheless, the consequence of having a crystalline array of waveguiding cones in our fovea is that the effective pupil size for optimal central vision is smaller than for the rest of the retina.…”

Inverse-Designed Aid Lenses for Precise Correction of Color Vision Deficiency

“…Recently, some researchers have developed metasurface- , or nanocomposite-based , aid lenses with narrow filter bands, resulting in a better correction effect. However, because CVD patients usually diversify in the wavelength shifts of their cone photoreceptors’ sensitivity, , none of the current methods can provide precisely customized narrow absorption spectrum for different kinds of CVD patients, resulting in dubious correction effects and unnecessary loss of their color perception experience.…”