Brigit Bara wrote:I checked the length of the rods and cones for comparison with light waves:
"the rod inner segments are 2 microns and the cone's about 6 microns in diameter in peripheral human retina. In the fovea, however, where there are only cone photoreceptors, the most central cones are even thinner than the average rod at about 1.5 microns diameter"
"The range of visible em waves consists of the narrow portion of the spectrum, from 0.4 microns (blue) to 0.7 microns (red)."
Is that what you were pointing out?
No, since I disavow the wave nature of light.
Rods and cones are a very interesting study in biological antennae, however.
A. Let's look first at the rod---
The discernment of dark and light is a simple matter of unidirectional or vectoral force [in the ideal]. Pressure toward the source [acc to CPFT] produces the sensation of light, while the relative lack of that centropic pressure is observed to be dark. The job of rods is primarily threefold, related of course directly to their structure:
1. As antenna for direct light pressure, rods detect no color, resonating only with the intensity of the signal at the direct line of sight. Thus, the "rodlike" structure is well suited to this LOS response. The LOS are to be distinguished from the central line of sight [CLOS] at the focal point of observation.
2. As motion detectors, the rods' peripheral concentration on the retina allows for quick recognition of not only motion but silhouette-ish form in peripheral vision. Subtle changes of color would be distracting to the quick acquisition of motion, a perception linked to survival. Rods nearer the fovea enhance the detection of detail particularly that elicited by shadowed/illuminated edges and light/dark edge transitions...
3. ...which enables them to be great for night vision. Observing objects at night, it provides much more detail to pan around the center of vision, allowing the rods to detect minute changes in the dark/light patterns not available in direct on viewing. I learned this as a young astronomer when I with naked eye discovered the rings of Saturn , and also observed the North American nebula late at night on a camping trip.
B. Cones, on the other hand, are better suited to the detection of the "conic" pressure gradient that surrounds the CLOS [central line of sight]. Cones are arranged and shape for color perception and [thus] detail in direct viewing at the focus of vision, being concentrated in the macula/fovea of the retina. A cone's broad "head" is able to elicit the pressure gradient about the CLOS, while it's internal structure transmits just portions of the gradient through the narrow "neck" of the receptor cell toward the brain. Thus some cones send signals from the "blue receiving" surface of the cone, some green, some red, etc. The density and distribution of the cones enables us to distinguish a million hues and amazing detail, particularly at the macula/fovea. The additional curvature/indentation of the fovea provides not only parabolic concentration of light but also the wider arc suitable [as an antenna] for the distinguishing of the pressure gradient about the CLOS.
Significantly the photoreceptors of the retina are positioned pointing toward the back rather than front of the eye, which is much more simply explained by the finding [ of the CPFT] that the light vectors are centropic
, in the direction of/toward
the light source/field centroid, rather than as material or pressure from
the direction of the source.
Now there's a creation story for you...