STRIPPED TO ITS ESSENCE……..PLEASE READ
November 30th, 2008 | No Comments »I have received a number of requests to summarize this explanation of the vision process. This is another attempt to do so / GCH
When my explanation of the vision process is stripped to its essence, the retina of the eye, and specifically the plane of retinal outer segments, is seen to be composed of an array of more than 130 million logically spaced nanowires that function to translate incident electromagnetic wave radiation into quantized electron particles. The quantized electrons encode the information necessary to form the visual image. The historically defined cone and rod receptors are seen to function as generic structural elements that function to provide the required spacing between adjacent receptors. The ratio of the diameters of these two sizes of receptors actually corresponds to the visual band, i.e., the ratio of -1.8:1 corresponding to the 700-400 nanometer visible band. We must stop thinking of receptors as cones and rods with different functions and realize that they represent simply two sizes of generic light conversion elements.
The lateral spacing of this nanowire array is determined by a simple geometric rule that selects three wavelengths from the broader electromagnetic spectrum for detection in the vision process. These are the same three wavelengths that have historically been termed primary that underlie the correctly understood trichromicity of vision
This geometric rule derived from the retina states that: an admixture of circles of two diameters defines three center-to-center wavelength-determining dimensions with the ratio of these two diameters defining the detected bandwidth.
Further, these three wavelengths are pre-selected by the light refractive chromatic aberrration of the structure of the evolved eye and focused onto the retina. This refraction has been historically and improperly termed an aberration but it is not an aberration at all but is fundamental to the visual image formation process.
In the largest sense then it then becomes clear that the true nature of the vision process is an objectification of the basic laws of the refraction of light and that the biological morphology of the retina evolved from simple and well understood molecular (chemical/polar lipid) self-organization mechanisms. Paraphrasing LaPlace “There is no need for a creationism hypothesis”.
The three wavelengths detected by the retina have historically been correctly defined as primary but improperly termed as colors. Early vision science discerned the trichromicity of vision but from that point picked the wrong model to explain it.
Thus, at the basis of evolved biological vision is a nanostructure that geometrically selects three wavelengths from the broader electromagnetic spectrum and translates these into quantized electronic information that is used to form the visual image.
The nanostructure of the retina evolved to detect light as an electromagnetic wave with the quantum transition to electron particle occurring at the point of retinal outer segments. The result instead of imagining that “a photon interacts…” should properly be termed more generally that a quantized interaction occurs. The traditionally used construction that photons interact with pigment molecules within retinal receptors was always inaccurate. And further, it is not and never was the case that “photons go from place to place”.
____________________________________________
For a discussion of the history of the concept of a photon read the paper “Anti-photon” by Nobelist Willis Lamb(Appl.Phys, B 77-84, 1995)
From the abstract of that paper.
“It should be apparent from the title of this article that the author does not like the use of the word “photon”, which dates from 1926. In his view, there is no such thing as a photon. Only a comedy of errors and historical accidents led to its popularity among physicists and optical scientists……”
So there!!!
But Richard Feynman believed in photons ! … from his “QED” p.15:
“I want to emphasize that light comes in this form - particles. It is very important to know that light behaves like particles, especially for those of you who have not gone to school. where you were probably told something about light behaving like waves. I’m telling the way it does behave - like particles.” (emphasis from F.)
This is like being told that there is no Santa Claus!
___________________________________________
Further, it must be emphasized that the individual light detection centers of the retinal array have dimensions smaller than light wavelength (i.e., they function in what is termed in physics the near field) and in a time scale of femtoseconds (10-15 seconds). These centers therefore serve to effect a fundamental quantized spacetime translation from wave to particle.
Following the initial light absorption process, energy is transported laterally (i.e., parallel to the plane of the retinal surface) along the lipid membrane that forms the structure of the thylakoid disks within receptors. This energy transport occurs via a phononic (or, as I propose, lossless solitonic ) mechanism that serves to thermalize the absorbed energy slowing the process down to human nervous system proportions, i.e., near millisecond (10-3 seconds). What has been termed the millisecond reaction time of the eye was always actually the reaction time of the human nervous system and not the eye itself.
Thus, the traditional morphological distinction between cones and rods can be finally understood. The function of the opsin protein moiety of the rhodopsin complex contained within receptors is actually structural with the purpose of it’s various perturbations being to effect the variable wavelength-defining spacing of the retinal array. Also finally explained is the, what has been termed, anomalous, dichroism of the rhodopsin light-accepting complex. We can now make sense of the laterally directed orientation of this molecular complex.
The incorrect idea that “cones detect color” and “rods detect black and white” quoted in every textbook on vision can now discarded. Use of the terms “primary” (as noted above) and “color” are now understood. The retina geometrically detects three primary wavelengths with the term “color” reserved to describe the synthesis of hues from these wavelengths as elegantly described by Edwin Land - when is someone going to realize this! Not unimportant in this regard is the finding of this work that the exact midpoint (near 550 nanometer) of the visual band that vision uses for “Land color synthesis” is geometrically determined. In one stroke a large part of the image forming logic used by the eye in vision is explained.
In summary, it can be seen that the “first stage” of the vision process functions in the realm of quantum physics with all that this portends.
One then imagines that we humans “peer out” into the broad electromagnetic spectrum that surrounds us through three narrow biologically evolved wavelength filters gathering information from that as yet only dimly understood regime of quantum physics - but we can now be sure that this is the case!.
The future of our understanding of the vision process seems linked to the domain of quantum physics.
GCH
Ojai, CA
