Rethinking the Process of Vision

(I have not included references in this post. They can each be found in the main of body of the work.. GCH)

The premise here for vision research is that a simple geometric explanation describing  the physics of  individual light interaction sites (or “pixels”) on the retinal surface leads to an entirely new understanding of the evolution of the eye,  the question: what is  “color”,  and the fundamental nature of the overall process of vision.

I have proposed that an entirely new and fundamental principle that combines geometry and the nanostructure of the retina of the eye is involved in light interaction with this surface. I have shown that this same principle and mechanism of light interaction applies to the photosynthetic organelles of plants and algae.

This principle  is totally at variance with the traditional (and abstract!) construction of quantum physics that has been unquestioningly carried over to  every textbook on vision, that “a light photon interacts with a pigment molecule contained within each cone or rod retinal receptor”.  How could this be wrong? But, this construction  has led, for example,  to such absurd  (i.e., without any theoretical or experimental basis) ideas as the “photon catch” hypothesis purported to explain the extended length of retinal light-accepting receptors. Utter nonsense accepted as gospel!

But most importantly, this  traditional line of thought is not (and can never be) consistent with the long accepted distribution of cone and rod on the retina (the measurements of Osterberg). That concept proposed that “classes of cones”  (the receptors that are thought to detect “color”) exist in some ordered  arrray on the retina. But this has never experimentally been shown to be true. AsI  have discussed (read the work!), cones  sensitive to “blue” have been almost vanishingly hard to locate. All of this in turn leads to the idea (again that cannot be justified) that the retina acts as the imaging plane where film is placed in a camera. All of this is totally irrational but has been propounded as fact for a hundred years!

As shown in Figure, I propose that each light interaction site on the retina is composed of two distinctly separate regions: A): a variable, wavelength-determinative space comprising the spatial distance between the centers of two adjacent cone or rod  receptors, and, B): a material-determined space of fixed dimension formed by a quantum-confined electron region of the ubiquitous (i.e., common to all receptors) retinal molecules contained within the body of each receptor. The result is a transition at the instant of light incidence from the classical wave nature of light entering the eye to a “particalized” electron that serving the electrical information processing function of the absorbing mass. THIS SINGULAR, INITIAL LIGHT INTERACTION EVENT OCCURS ON A TIME SCALE. OF FEMTOSECONDS (OR 10-15 SEC) AND HAS NOTHING TO DO WITH THE SLOWER “REACTION TIME” OF THE EYE. There is evidence for this in  the long established (but never explained) measurements of the isomerization (i.e. “signal producing”) time of the retinal molecule showing that this molecular “mechanical” event takes place in the same femtosecond time domain.

Figure 1 illustrates in the abstract the situation where the two adjacent receptors that comprises the two above described regions. As initially shown, these receptors have the same spatial diameter such as would be the case for two adjacent cones or rods. The retinal surface, however, actually contains chiefly (no quibbling!) two receptor diameters that have traditionally been termed  the cones and rods. As shown geometrically in Figure 2, and following many measurements over the years, the ratio of the diameters of these two types of retinal receptors has been determined to be very close to 1.8:1 with the larger diameter abstract circle representing  a cone and the smaller a rod.

Now to considerations of purely abstract geometry that directly follow from this retinal characteristic. First, this ratio of 1.8:1 corresponds to the width of the visual band, i.e., from 700 to 400 nanometers. Lest anyone doubt  the validity of this ratio it can easily be seen that this ratio results in exactly eight of the small circles fitting around one of the large circles and  that this is the motif found on the human retina at 8-9 degrees of retinal angle (see Osterberg). And even more surprisingly, this same “eight-around-one motif is seen in the visual organs of seemingly all species (see Snyder).

Therefore I would propose that the ratio of the sizes of the two circles (or two sizes of receptors if such appear on any retina) determines the width of a visual band.

Further,  it follows that the geometric (center-to-center) distance  corresponding to appositions of the larger circles (i.e., the “cones” that comprise the central fovea of the human retina) determines the exact long wavelength limit of the visual band. Correspondingly, this appositional distance of the smaller circles (the “rods”)  determines the exact short wavelength limit of the visual band.

Thus it is geometry that determines both the width and the exact endpoints of the visual band.

Again to quote Einstein “All is geometry”.

Then to perhaps the crucial factor that is geometrically determined - it  follows that the appositional distance of a large to a small circle (i.e., a cone-to-rod distance) must correspond to a geometrically determined exact mid-band wavelength, at 550 nm.

Thus a geometrical construction - or distance - is fundamentally associated with a specific light wavelength.

I would propose that this fixed geometrical reference corresponds to  Edwin Land’s  “fulcrum” wavelength that he deduced must be present in the eye. This is the reference that  the eye uses as to synthesize the hues of color from light intensities absorbed on either side (Land’s long and short wavelength “records”).  The term “color” enters here for the first time! The eye fundamentally detects three narrow band, geometrically determined wavelengths although in the history of vision science these have improperly been termed the “primary colors”.  They should  be termed primary “wavelengths” as they are not yet the hues of color!

These purely geometric considerations seem to explain Land’s brilliant deductions about the mechanism of color vision that he made from  measurements made external to the eye.

The central finding of this work follows directly from the above considerations.  Using Osterberg’s classic 1935 measurements of the distribution of cones and rods on the retinal surface (that no one disputes), the three primary wavelength peaks described above arise  simply “counting” the three types of receptor apposition (i.e., cone-cone, cone-rod, rod-rod) as a function of retinal angle. See Figure 3 in the main body of this work.  THESE ARE PEAKS OF THE DENSITY OF LIGHT SENSITIVE CENTERS. The central fovea that contains >99% of the large (i.e., cone) receptors is solely long wavelength sensitive and, as described above, exactly determines the long wavelength  limit of the visual band. The concept of the existence of “three classes” of cones has been a fundamental  error in the history of vision science! The wavelength peak defining the geometrically determined mid-band “fulcrum” is seen to exist at angles of 8-9 degrees where (see Osterberg!) the morphology consists of aNn entire area-encompassing motif of eight rods surrounding each cone. In viewing Osterberg’s data this is very striking!  Beyond this angle the retina consists almost solely of rod receptors with these rod-rod appositions  determining the exact short wavelength limit of the visual band. It seems that the retinal area from which the visual image is derived extends from the fovea to perhaps 20 degrees of retinal angle. I have proposed that the peripheral rod-containing retina functions as a “wide angle light meter” that controls constriction of the pupil of the eye.

Further, the plan of wavelength interactions on the retinal surface is totally consistent with computer simulations of light refraction within the body of the eye. It is almost ncomprehensible to me why this has not been seen!

And further, the lesson at the basis of these geometrical considerations is that the structure of the eye evolved in consonance with the physical principles of the refraction of light. There is no need for any “design”. I have written about this elsewhere on this webpage.

I would note finally that all of this is predictive that is the requirement of any new concept. I have noted some preliminary examples in the body of this work relating the retianae of fish and insects to the characteristics of their visual response.

Respectfully submitted,

GCH
Tucson, AZ
7.31.09

I repeat a comment  that I wrote in 2008 noting that, following from this explanation, “green light interactive centers” (NOT cones!) would predominate at retinal eccentricities of 8-10 degrees. I addressed repeated requests to the individuals who had made previous measurements at a smaller retinal angle (at one degree or  the edge of the fovea) where, as should be the case in this transition region, they found a totally random distribution of “the three types of cones”. As discussed below they found at larger retinal angles what they termed “clumping of green cones” - exactly as this explanation predicts. In the paper publishing these results nowhere do they acknowledge my request or include any reference to this work. Perhaps they haven’t noticed (?)

FOR THE RECORD: WHAT THEY, AND THE BROADER VISION SCIENTIFIC FIELD,  TERM  “COLOR SENSITIVE LIGHT DETECTING CONES” ARE ACTUALLY LIGHT DETECTION CENTERS FORMED BY THE APPOSITION OF A LARGE DIAMETER CONE TO A SMALLER DIAMETER ROD. MOREOVER,  THESE INDIVIDUAL CENTERS DO NOT YET DETECT WHAT WE TERM THE HUES OF “COLOR” BUT RATHER THE THREE DISCRETE “PRIMARY” WAVELENGTHS THAT DEFINE THE ENDS AND EXACT GEOMETRICALLY-DETERMINED MIDDLE OF THE VISIBLE BAND.  THE HUES OF COLOR RESULT SUBSEQUENTLY FROM RETINAL PROCESSING OF THESE THREE PRIMARY WAVELENGTHS AS SHOWN BY EDWIN LAND.

The original Comment:

A paper (3832/A375) was presented at the ARVO 2008 Annual Meeting “Arrangement of the Human Trichromatic Cone Mosaic in Peripheral Retina” authored by O. Masuda, H. Hofer, J. Carroll and D.R.Williams. I interpret this work extending the imaging methodology developed by the authors (and previously by Roorda et al) to larger retinal eccentricities, as being in some way a response to my repeated requests that this measurement be made.

I humbly submit that their results seem to verify my projection in their finding of a “clumping” of, what they (erroneously) term L and M “cones” at retinal eccentricities of 10 degrees. They note that this represents the first instance where the packing arrangement of cones is distinguishable from randomness, i.e., that a spatial order is observed. Their exact statement “Previous studies have concluded that the packing arrangement of L and M cones near the center of the human fovea is not distinguishable from random in most eyes”. (does this mean that the packing arrangement in “some” eyes is not random? – please supply a reference?).

I believe that the basis for what they are observing follows directly from my observation that is calculated directly from Osterberg’s measurements of retinal topography showing that the maximum (at this point complete!) degree of spatial order appearing as a motif of eight rods surrounding each cone. This perfect geometric array following Osterberg occurs near this eccentricity (really at 7-8 degrees but they are close enough). The interplay of cones and rods at this eccentricity is not statistical anymore but completely ordered! I have proposed that this octagonal motif forms a fundamental (termed “primary”) mid band (“green” or in their terms an “M cone”) light interaction point on the retina. In my explanation this complete degree of geometric spatial order translates into the peak of intensity of the primary mid band wavelength and forms the 550 nm wavelength mid band reference point on the retinal surface. I have proposed that the identification of this geometric reference forms the basis for the color constancy of vision. The eye interprets the exact middle of the visual band geometrically! The retina is not a spectrometer!

I will not go into this much further only noting that the sample size of their images is so small that the statistical nature of the distribution of cones and rods is seen (Osterberg again!). This is as to be expected and they note this. The first degree of order (or “clumping”) that they observe at the 10 degree eccentricity in these statistically small images represents the “tip of the iceberg” of the spatial order that exists at this eccentricity. Their quest for an ordered “mosaic” on the retina, and any idea as to how the randomness that they have observed (until now!) could lead to an image formation mechanism, totally eludes me. I would like to see the reasoning behind this?

The spatial resolution of their imaging methodology and the question why they do not observe rod receptors? I have addressed this in a previous Comment. Suffice it to note that they claim 2 micron resolution which would be approximate the diameter of the inner segment of a single cone and should be sufficient to image rods .

Again, I would claim what they are actually imaging at this eccentricity is a motif of eight rods around each cones. This “M cone” should be really be termed an “M wavelength detection center”

Added on 5/14/08

The authors also undertake a curious (to me) effort to measure the distances between cones apparently to verify the randomness of the distribution. I do not understand why they apparently want to verify what already is, and should be, apparent as the statistical randomness following from the Osterberg morphology data? Their words: “We evaluated the packing arrangement of the 3 cone classes by comparing frequencies of distances between all cones of the same type with those expected based on a random pigment assignment rule”

To be clear - the foveal region that contains > 99% of cones on the retina, and where they want to see a differentiation of these cones into “classes”, is totally “L wavelength” sensitive. Then as rod receptors begin to intrude into the receptor array at the edge of the fovea at eccentricities of one degree a statistical distribution of L and a few M (cone/rod appositions) begins to be seen. At this point if one does not want to believe the data of Osterberg see the figures of George Wald! The author’s measurements until this paper were made at eccentricities of one degree and they observe exactly what they should observe. I would note on the subject of “S” or blue sensitive “cones”, again statistically, here and there an apposition of two adjacent rods will be observed ..and voila, an “S” cone! This is the explanation for the strangely small density of this type of “cone”.

My finding of the three primary wavelength peaks on the retina follows from a simple counting of receptor appositions using Osterberg’s morphology data. Any grad student could do a statistical analysis of the presence of rod/rod appositions in near foveal region (at an eccentricity of one degree as measured by Roorda) and I project that the density so calculated would correspond to these measurements of “S Cones”.

Respectfully submitted.

GCH

5/14/08

The following is a portion of text from a letter responding to a technical query of mine:

“……….I seem to recall though that modern molecular biology has yielded protein sequences for rod and cone pigments”

Plaintively.…doesn’t anyone yet understand the simple  geometric light interaction principles underlying this explanation - that finally makes sense of Osterberg’s historic retinal morphology measurements ? Cannot anyone get past the incorrect concept that “retinal pigments contained within receptors” determine light interaction on the retinal surface - and the subsequent absurd , historically propounded, notion that “cones detect color and rods detect black and white”!

But, to the point of this text, any modern genetic finding such as this (“modern molecular biology has yielded protein sequences”) really represents an incomplete statement.  The  important question to ask in this case is:  sequences to produce a protein structure that functions how? If one assumes that it is “to construct a pigment molecule” then one is irrevocably stuck in the old incorrect model of retinal light interaction. I continually find the awe that contemporary science holds for genetic knowledge assuming that this capability in itself explains “everything”  when in fact  this knowledge is only an intermediate step towards explaining anything.

In my explanation, the sequences to which the correspondent refers lead to construction of the spatial “framework” of the rhodopsin complex that “holds” the central retinal molecule (that is ubiquitous to every receptor)! This genetically determined spatial  framework differs for the two sizes (cone and rod) of receptors.

The role of the protein sequences in this new explanation is to provide a geometric spatial function.

Please read the work!

GCH
Tucson, Az
7.06.09