Rethinking the Process of Vision

Based on this explanation of the vision process, I have speculated that there might be a geometrical symmetry lurking in the realm of seemingly structureless biology (search the term ‘epitrochoid’ on the homepage to see various entries on the subject).  It is probably time to recycle this idea.

At least two points might serve as a starting point in this line of thinking. First, there is the curious finding by Snyder (ref. in the body of the work) that the same octagonal symmetry (i.e., that eight rods surround each cone in the retinal motif) found on the human retina seems to be characteristic of the visual organs of seemingly all species from crabs to honeybees. This occurs on the human retina at 7-8 degrees of retinal angle and I have shown that this motif geometrically defines on the retinal surface the exact center (~550 nm) of the band of wavelengths that encompasses the visual band.

I have also noted that the finding of this precise geometric definition of wavelength on the retinal surface is probably the basis for the color constancy of vision.

Further, this octagonal motif is the singular result of a ratio of the diameters of receptors (cones and rods) of 1.8:1. This, in turn, is consistent with many accepted measurements of the physical size of cones and rods. I have noted that this same ratio –the ratio that results in octagonal symmetry - corresponds to the band of wavelengths to which human vision is sensitive – from 700 to 400 nanometers. Thus, might we speculate that the visual band is geometrically determined?

It follows from this explanation that it is the absolute diameter of receptors that determines the placement of the visual band. Smaller diameter receptors would result in sensitivity toward the UV with larger receptors sensitive to extension into the near infrared. I have noted that this seems to correlate with the retinas of insects and birds (UV) and fish species (near IR). The ubiquitous octagonal motif, however, dictates that in whatever band of wavelengths the species is sensitive the bandwidth will be the same.

One might begin to believe that there is something curious lurking in the octagonal motif !

It occurred to me long ago in playing with the octagonal motif that it presented a singularly unique situation in the formation of epitrochoid structures. Specifically, the eight-around-one motif (again, that results from the 1.8:1 ratio of sizes) produces a unique spatial symmetrical epitrochoid. (this symmetry was the basis for Felix Wankel’s rotary internal combustion engine).

(a reminder to the reader – an epitrochoid is the figure that results from following a fixed point on the radius of a circle that is “rolled around” a second circle).

The following figure that I used a long time ago. As above, the epitrochoid assumes that ‘something is revolving around something’ – that is not at all in evidence from light interaction with the retina – but the finding of a correlation between the octagonal motif and a symmetrical structure seems curious.

The asymmetric epitrochoid at the top represents the all-cone structure (or, in the context of this work the ‘long wavelength sensitive’ region) termed the fovea. A unique symmetrical epitrochoid results from the octagonal motif, with, again, asymmetry in the all-rod region (genrally beyond 20 degrees).

Perhaps the most fundamental aspect of this explanation of the process of vision is that pure, rigorously geometrical or dimensional, factors effect the exact determination of wavelength in the certainly non-rigorously geometrical realm of biology.

THIS IS AN INSTANCE OF A GEOMETRICAL FIGURE AND ELECTROMAGNETIC WAVELENGTH BEING DIRECTLY RELATED.

THE EYE SENSES THE EXACT MIDDLE OF THE VISUAL BAND AT ~ 500 NM GEOMETRICALLY.

But the idea of symmetry…and following the Olive Sacks comment (see previous) that ‘Landian’ correlations seem to take place in the vision centers of the brain…..might the concept of a spatial ‘nanostructural symmetry’ follow onward from the retina to perhaps new insights into the functional mechanisms of the brain? The unexpected occurrence of a ‘geometrical spatial symmetry’ in the biological realm…..??????

I am reminded here of a quote from Roger Penrose:

“There is, in fact, at least one clear place where action at the single quantum level can have importance in neural activity, and this is the retina (recall that the retina is a part of the brain).”

GCH

A piece from the New York Times of February 11, 2010 “From That Instant Thrill, Enduring Art, Now for Sale” recounts a melancholy end to a great man’s dream. The piece refers to the history of Edwin Land and Polaroid instant photography.

The seemingly total lack of interest in Land’s color vision work has been a great surprise to me ever since I began writing about vision.  The few comments I have received have been decidedly negative in tone (such as “…..we put Land’s work to bed years ago….”) and, really, much worse.  I  vaguely remembered Land’s astonishing color vision experiments and the attention they received in the 1950’s, even being featured on the cover of an issue of Scientific American of that era. My initial feeling in 1991 when I began this effort was that Land’s  work must somehow  have  been explained in the intervening fifty years … but alas … nothing in the literature.  Land and his body of work on color vision just seemed  to have disappeared !

To summarize the situation today in the light of my explanation for light interaction with the retina seeing it as a diffractive surface  finally provides the factual basis for understanding Edwin Land’s prescient color vision experiments.  I have written extensively on this subject  (one might search the term “Land” on my homepage, ghuth.com).

I will here only recount what is perhaps the central piece of evidence - the geometrically determined reference point  on the retinal surface that I precisely define as the exact middle of the visible band at 550 nanometers (at 8-9 degrees of retinal angle where the density of rods is sufficient to surround each remaining cone in octagonal symmetry).

To quote Land: “…we have learned that the eye must have a fantastic mechanism for finding a balance point within a band of wavelengths”. He went on to term this point a “fulcrum” in the band of wavelengths to which the eye was sensitive.

I submit that this balance point has now been found!

Land did not have the benefit of my explanation so he therefore attempted to fit his observations into the existing (and incorrect) model of the eye. The result was his brilliant but convoluted “Retinex” theory for color vision.

I solicit the interest and collaboration of anyone still interested in Land’s work. He was truly a singularly brilliant individual!

GCH,

Ojai, CA

02.13.10

I have noted in a number of previous Comments what I thought were important findings by  Engel et al  of , using their terms, “…. a wavelike energy transfer through quantum coherence in photosynthetic biological systems”. The subject of their measurements were a type of antenna protein in green sulfur bacteria. In quantum term, coherence is defined as an unexplainable  ‘multiple state of existence’. It is crucial to note that the existence of this quantum coherent wave energy transfer mechanism emerged from measurements that employed ultrafast (femtosecond or  10-15 sec) spectroscopy. Also, that these observations required cooling to temperatures below -300 degrees Fahrenheit.

A new paper published in Nature by Greg Scholes of the University of Toronto reports similar femtosecond specroscopy measurements made of a simpler light harvesting  marine algae structure with a finding of quantum coherence at room temperature. To quote: “they found that energy patterns in distant molecules fluctuated in ways that betrayed a connection to each other (1), something only possible through quantum coherence”. The review of this paper suggests that such quantum coherence is ‘routine’ in nature.

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(1) This statement again conjures up the notion of ‘quantum magic’, i.e., from “betrayed a connection…etc”. What is observed in these results, however, is a real wave-like energy transfer connection that exists in the very fast, femtosecond  time domain, One should realize that measurement in this time domain represents a new capability for us. This would seem to explain why we have not observed this behavior before. Taken together with my explanation for light interaction with the retina, it may be that  we on the threshold of exorcising the magic?

Again, I have proposed that the nanostructure of retinal outer segments consists of individual light detection elements that function in the near field of light, i.e., at dimensions smaller than the wavelength of light. The actual dimensions of these centers consists of a micron (or sub-micron) dimensioned, wave-accepting space or spaces (the distance between individual receptor centers) that are necessarily adjacent to quantum confined electron areas that are of smaller nanometer dimension. This is the basic light detection ‘device’ of the retina. It follows that elements of these dimensions will possess the ability to function (absorb the light wave and transfer that energy to a quantized electron) in very fast time consistent with the above findings. The outer segment of the retina functions in the quantum domain !

It then follows, as I have proposed, that overlap of individual light detection events (that results in cancellation of signal) is eliminated (by simple Poisson calculation) by the speed of response of these elements. This would seem to explain the ability of the eye to sense single photons (really ‘quantized events’) and the extrordinary light collection efficiency of biological photosynthetic structures.

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To continue…

I had noted in a Comment of 12.02.09 “Two Separate Regions of the Retina Function to Effect the Vision Process” that the nanostructure of the outer segments of retinal receptors functions in the femtosecond or quantum time regime consistent with the above findings of a new quantum coherence effect. There has even been longstanding (and unexplained) evidence of this in vision literature where isomerization of the (the ‘electron signal producing event’) retinal molecule contained within retinal receptors occurs in this time region.

I would note that I believe, and have proposed in the body of this work that the same classical/quantum mechanism that functions in light interaction with retinal outer segments also operates in plant photosynthesis. The ‘wave-accepting’ areas of the nanostructure, configured in the eye to produce an imag, are simply arrayed in parallel in the biological photosynthetic structures of plants and algae. This is even obvious!

I believe that these two papers  reporting a quantum coherence effect in biological photosynthetic systems are of significant importance. They represent the vanguard of a new quantum biology and will led to a more fundamental understanding of the vision process.

And the explanation for the vision process that I propose in this work will lead there!

GCH
Tucson, AZ
2.03.10

The following figure is Osterberg’s classic measurement of retinal topography that  was published in 1935. It represents the distribution of cone and rod  receptors of the retina over the area extending from the central fovea to the periphery. This figure has been referenced countless times in vision textbooks since it was published and has now been broadly accepted as the  correct interpretation.

This new explanation for the vision process derives entirely from a new interpretation of this single figure.

I would note that these measurements show that over 99% of receptors termed ‘cones’ are found within one degree of retinal (or ‘perimetric’ ) angle. This region comprises the area that is termed the fovea.  Extending beyond this point to larger angles, the smaller ‘rod’ receptors are statistically introduced into the all-cone matrix to spatially displace the rapidly decreasing density of the larger cones. Thus, beginning at the edge of the fovea (i.e., at one degree) the morphology of the retina is composed of  a statistically distributed admixture of’ cones), rod-cone appositions (misconstrued as ‘green sensitive’ cones) and a statistically few rod-rod appositions (that have misconstrued as ‘blue sensitive’ cones).  Statistics explains the historically noted mysterious paucity of ‘blue cones’. Attempting to see the overall picture, this is important - there is no  ostensible regular spatial ordering of either receptor.

There is, however an angle that is of crucial importance where a spatial order is found. This is in the region from 7-8 degrees where for the first time sufficient rods are present to completely surround each cone. The rods do so form this particular order resulting in an octagonal symmetry (1). The relevance of this spatial order has not to my knowledge been realized prior to my work. This morphology is shown in the following taken from Pirenne (referenced in the body of the work):

(1) I am going to digress her to note that this same octagonal symmetry of retinal receptors is found in the visual organs of seemingly all species from crabs to honeybees  (the work of Snyder - again referenced in the body of this work). Octagonal symmetry can only result when the ratio of the sizes of the two receptors is 1.8:1 and this corresponds to the size ratio of cones to rods in the human retina.  This ratio also corresponds to the visual band - from 700-400 nanometers. The basic tenet of this work is that “all is geometry”.

At this point one might reflect on the long accepted mantra (again, presented in almost every textbook or discussion of vision !) that “it is the cone receptors that detect ‘color’ and the rods that detect ‘black and white’”. In fact, even further, how can such a statistical distribution of light detection elements lead to any rational image-forming process?

There has always been in my view a glaring irrationality as to how Osterberg’s measurements and this statistical distribution can be interpreted in understanding any sort of image formation in the vision process. The eye has certainly been viewed historically in the literature as the analogue the ‘camera’  that we know and understand as the technological method that we use for forming images. In this construction the retina is then placed at the plane of the optics of the eye where film (or in this latter day, the ’silicon imaging chip’ in a digital camera) is placed in such a camera. This plane is termed the ‘image plane’ where the film etc,, is sensitive to only the intensity of light falling onto it. This view goes further to assume that other aspects of the operation of a camera such as a ‘frame integration time’ must be characteristic of the biological vision process. These processes are very slow - of the order of milliseconds or 10-3 sec  - and this has been thought to be the time domain in which the processes of vision operate.

It seems, however, that film or an of our other imaging modalities always require some sort of organized spatial distribution of light detecting sites (’pixels’) to encode an image. This presents the situation of the  ‘great unavoidable disconnect’  between the spatial order in the distribution of  light detecting sites in photographic film (or on a silicon imaging array ) and the  purely statistical distribution of such sites on the retina that follow from the measurements of Osterberg. How can one persist in making this analogy?

The answer has been to assume, in attempting to explain color vision, that there are really three ‘classes’ of cone receptors (a red green and blue variety) and that these, although no one has yet succeeded in finding any logical spatial distribution of such receptors that would  somehow lead to the formation of an image. Even if this distinction as to cone classes were real the cones are still statistically and randomly distributed - and even further, the blue variety are in very  very short supply and are seldom seen! Questions?

I am going to note here that in this work the reader will see the that the  fundamental idea assumed above that it is the cone  and red receptors  themselves that detect light, according to my explanation, is totally incorrect. Even the invocation of the term ‘color’ at this point of the discussion is incorrect and this has led to a gross misunderstanding in explaining the vision process. All of this will become clear in the following.

Initial motivation for this work followed from by an increasing body of work in the 1990’s to the point that light was detected in the nanostructural domain by spatially dimensioned  ‘antennas’ structures (1) in contrast to the, accepted in modern times,  ‘pure-quantum’ construction assuming that ‘a photon interacts with….pigments….”.

(1) Particularly, a A U.S. patent  4,445.050 by Alvin Marks “Device for the Conversion of Light Power to Electric Power”.

With this concept in mind, and I must add with a singular flash of insight, I used the Osterberg data to simply count the number of  receptor appositions (i.e., center-to-center distances between receptors) at each retinal angle. This very quickly revealed  concentric  rings of three distinct  peaks or regions on the retinal surface that for the first time seemed to me to provide a rational explanation for the measured distribution of receptors . The first peak, as shown in the figure generated by this process, was centered at less than one degree of angle by cone-cone appositions, the second peak at ~7-8 degrees of retinal angle corresponding to the peak density of cone-rod appositions, and finally, the region beyond  ~20 degrees to the periphery of the retina where rod-rod appositions predominate.

I thought at the time that these peaks or regions might explain what had been termed the three primary ‘colors’ that has long proposed to underlie the trichromicity of the vision process. (I am going to note here again that these should at this stage properly be termed ‘wavelengths’ - they are NOT YET  ‘colors’)

I was at the time using optical simulation software (‘LightTools‘ by Optical Research Associates) for another project and decided to enter (even in rather cursory fashion) the optical parameters of structures of the eye to see if the wavelength/angle interactions calculated above were reasonable. It very quickly became apparent that the three wavelengths fell very close to these positions on the retina(2).

2) I very shortly thereafter visited a nearby fellow engaged in computer simulation of  light refraction in the eye with  far more precision than I had been able to do (I believe for LASIC application). Almost magically, with one touch of his computer, and on a very large computer display, up came  the exact locations for wavelength interactions on the retina that I had calculated above!  I remember his comment after politely listening to me that he would have to “re-learn all that he had been taught about vision if he were to believe me“!

AT THIS POINT ONE MIGHT REALIZE THAT A.) THE RETINA IS A DIFFRACTOMETRIC STRUCTURE THAT RESULTS FROM THE REFRACTION OF LIGHT WITHIN THE EYE. THE EYE EVOLVED TO DISCERN WHAT HAS BEEN TERMED AN “ABERRATION”- THE CHROMATIC ABERRATION OF THE EYE. THIS, IN TURN, CATEGORICALLY PROVES THAT THE RETINAL PLANE IS ACUTALLY  THE FOURIER OR FOCAL PLANE OF THE EYE. AND FURTHER, THIS MEANS THAT EACH LIGHT DETECTION ELEMENT ON THE RETINA MUST BE CAPABLE OF ENCODING BOTH THE INTENSITY AND PHASE OF LIGHT. I SHOW HOW THESE ELEMENTS PERFORM THIS FEAT.

ALL OF THESE THOUGHTS  DERIVE FROM WAVE OPTICS - THE EYE EVOLVED TO INTERACT WITH LIGHT AS THE WAVE OF CLASSICAL PHYSICS SUBSEQUENTLY TRANSFORMING THE ABSORBED LIGHT ENERGY INTO QUANTIZED ELECTRONS FOR PHYSIOLOGICAL USE.

This distribution of wavelengths on the retinal surface then must correspond to what has been termed  the chromatic aberration of the lens and structures of the eye. As I will show this distribution does not represent an aberration at all but the basis for the image forming mechanism operative in the eye. The distribution of receptors measured by Osterberg now can be for the first time be rationally explained!

Such a concentric distribution of three discrete  forms of light detection sites can only mean that the retina is actually a diffractive surface that interacts with incident light. This, in turn, implies that the retina is located at the Fourier or focal plane of the optics of the eye and therefore that the Fourier equation must be satisfied in forming the visual image. Therefore, light detection sites on the retinal plane must be capable of encoding both the intensity of detected light but also the phase of such light rays. In deducing how an image is formed, phase would encode the direction of light rays at  the point of detection. I have proposed that the nanostructure of the appositional outer segment light detection devices of the retina possess exactly this capability as I have diagrammed in the following:

One must differentiate here between the location of the retina in the traditionally assumed ‘camera’ analogy (described above) and image formation at the Fourier plane. The film or silicon digital imaging chip in a camera is placed at what is termed the ‘image plane’ where only the detection of  light intensity at each point  is used to form an image.  This type of forms the basis for our entire technological capability in manipulating visual images. We  simply have not developed the capability for detecting both the intensity and phase in  single device as the eye has!

The retina forms the Fourier or focal plane of the optics of the eye!

It must be remembered at this point that each of these newly defined three wavelength sensitive regions that form the Fourier plane of the eye following from their precisely constant dimensions are ‘tuned’  (in antenna terms) by this nanostructural geometry to narrow, even single, optical wavelengths. These wavelengths are indeed primary, in accordance with what had been historically deduced by Young, in that they will  subsequently be used to determine the hues that we term ‘colors’.  This term, however,  must not be used in their description!

This point is crucial with the use of this term at this point of the light detection and imaging process having caused irreparable harm to the science of vision!

The hues of color do not yet exist at the point of light detection at the plane of outer receptor segments - only three discrete wavelengths.

This will become clear in what follows, but it should be clear that the three wavelength detection sites on the retina are not three ‘classes of cones’, indeed they are not cones at all. I have written extensively on this subject in the body of this work and my view has now been experimentally verified (2) The sheer irrationality of this assumption following Osterbrg’s measurements boggles the mind…“cones are the detectors of color”….”most cones are contained in the fovea at less than one degree angle”…..”there is no discernible spatial ordering of cones that would be required for imaging logic”…”the blue variety of cones are present in only vanishingly small numbers”…and on and on !!!

(2) I will digress here to make the important point that in my view the distribution  of wavelength  detection  centers that I find, and thus this entire new explanation of the vision process, has actually been experimentally validated. I discuss this at length on ghuth.com. A Berkeley group  (Roorda et al, “The Arrangement of the Three Cone Classes in the Living Human Eye” ) developed exacting  methods for   imaging single color (the term color again inappropriately used!) detection centers on the retina that they attributed to response of  single cones. This work would  purportedly verify that  three types of cone receptors exist. I noted that their measurements were made at the edge of the fovea (at ~1 degree of retinal angle) where the density of cones is very abruptly decreasing and the insertion of rods becoming increasingly evident. In short, in my view they saw exactly what they should have seen occasioned by the presence of  cone-cone appositions (that they pseudo-color red), an increasing density of cone-rod appositions (colored green) and, here and there as would be expected, a statistically small density of rod-rod appositions (colored blue). Bothersome to them is that there is no apparent order to this distribution - it appears that these cones are randomly distributed! I requested repeatedly that this, or some other, group ,using these imaging methods, make the same type of measurement at 7-8 degrees of retinal angle and that such a measurement would reveal a density of, continuing to use their incorrect terminology, ‘green sensitive cones‘. A paper (3832/A375) was presented at the ARVO 2008 Annual Meeting “Arrangement of the Human Trichromatic Cone Mosaic in the Peripheral Retina” by Masuda et al. ( I cannot find a link to this paper) that, according to my projection, found what they termed a “clumping” of green (they term “L”) cones at 10 degrees. They also note that this is the first time that spatial ordering of such cones had been found. All of this is in consonance with my explanation - but no response or association with my requests!

To be continued……..

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I AM GOING TO STOP HERE AND PUBLISH THE ABOVE. BUT…THE BEST IS YET TO COME…..THE NEW AREAS THAT THIS VIEW OPENS FOR STUDY …’NANOSTRUCTURAL GEOMETRIC EFFECTS’….’THE DISCRETE SEPARATION OF THE QUANTUM ASPECTS OF VISION  FROM THE SLOWER PHYSIOLOGICAL PROCESSES’….’THE POTENTIAL FOR STUDY OF A CONNECTION BETWEEN VISION AND EXTERNAL CONSCIOUS REALITY’..AND MORE….

GCH
2.02.10
Tucson, AZ/USA