Optical Sensitivity of Camera-Like Eyes to White Light

Gastropod mollusks are convenient model organisms for studying the functioning of the visual system. The purpose of this work is to estimate the value of the optical sensitivity to white light for the camera-like eyes of gastropod mollusks and humans and analyze its effect on the spatial resolving power in two regions of the retina: in the center—for single photoreceptors of the first/second type in a mollusk and single cones in humans—and in the periphery—for single photoreceptors of the first/second type in a mollusk, as well as for single rods/cones and their groups, subject to spatial summation in humans. The methods of histology, light and transmission electron microscopy, morphometry, calculations and methods of statistical analysis are used in the work. In a mollusk, with a fixed pupil area, the value of the optical sensitivity of the eye to white light in the center of the retina for single photoreceptors of the first/second type is 0.5/0.006 μm2·sr and in the periphery of the retina, 0.9/0.009 μm2·sr. In humans, at the minimum and maximum pupil area, respectively, the value of the optical sensitivity of the eye to white light in the center of the retina (foveola) for single cones varies from 0.00053 to 0.028 μm2·sr, and in the periphery of the retina (far periphery) for single rods from 0.011 to 0.575 μm2·sr, for single cones from 0.025 to 1.319 μm2·sr, for the groups of rods from 3859 to 204,094 μm2·sr and for the groups of cones from 2.5 to 131 μm2·sr. The value of the optical sensitivity of the eyes to white light for single photoreceptors of the first/second type in both regions of the retina in a mollusk, as well as for single cones in the center and groups of rods/cones in the periphery of the retina in humans, corresponds to the ambient light conditions during periods of activity and does not affect the spatial resolving power.