I have previously written on this subject (simply search the site using appropriate terms). My thoughts today after reading an article in the New York Times of October 25 “Plugging Into the Eye, With a New Design” by Anne Eisenberg. I have two thoughts  - one on the topic of how these developments are presented in the popular press and the second technical.

First, it pains me that the piece leaves the sight impaired with the hope that the concept of a retinal implants will ultimately restore their sight. The beautiful figure  of an artificial eyeball shown in the piece certainly gives this impression. The fact is, however, that the best that these devices can do, in the  actuial words of the piece, “Most retinal prostheses seem to function to let people detect light and dark”. This is really what I might expect to result when one inserts something near or behind the retina – something happens! When one considers the problem of coupling of such crude imaging devices to the optic nerve…… a nerve bundle that contains some eight million individual fibers……?

I really do not want to be overly negative about these developmental efforts that are being carried out in many parts of the world. This work is only in the very early stages and, again from the piece, “The eye adapts” may prove to be the operative thought and some improvement in vision may ultimately result.

But……..

The point that I have continually made, that forms the fundamental teaching of this work, is that the eye does not function as a camera, i.e., making the assumption that the retina is located at the intensity-only-sensitive “film” plane of the eye. Coming closer to the pixilated solid state devices that are being developed, the assumption is made that the eye behaves as a digital camera. As far as I can determine this is the principle that underlies all of the retinal prosthesis developments that I have seen.

But this is not the case as I explain. Following from Osterberg’s classic retinal morphology measurements, the retina is seen to be a diffractive surface (implying that it forms the Fourier of focal plane of the eye). Now…we do not currently know how to fabricate the retinal light detection elements (i.e., sensitive to light intensity and phase) but, again from this work, we do now know (exactly!) where light wavelengths interact on the retinal surface. Read to the body of this work, but I refer to the finding that the central fovea is solely sensitive to long wavelength (“red”), 550 nm mid band at 8-9 degrees of retinal eccentricity etc.

Again, we do not yet know how to replicate the light detection devices of the retina, but, it would seem to me that application of this knowledge could lead to prostheses that at least begin to mimic the actual process of vision.

And….I believe that technology is available to actually fabricate in silicon the actual light interactive properties of the retina from the fovea to 20 degrees of retinal eccentricity.

I would, as proposed in the past, like to collaborate with any group in this endeavor.

GCH

Ojai, CA

This statement represents a deadly shortcut that is the origin of the mistaken view of vision that has been taught for hundreds of years.

The eye is certainly an “optical system” and an “optical image” is certainly the finality, but the steps between differ fundamentally from the camera analogy conjured up in this construction.

The overly simplistic camera analogy implies that the retina is located at the intensity-only sensitive “film” or image plane of the eye. I demonstrate directly using Osterberg’s classical retinal morphology data that this is not the case.

The retina is actually a diffractive surface implying that it is definitively located at the Fourier or focal plane of the eye. This in turn, means that individual light detection elements of the retina, to satisfy the Fourier equation,  must possess the abiity to detect both light internsity and phase of detected light. I have described the light detection structures of the retina that accomplish this.

How long will it take vision science to understand and correct this ?

GCH

Ojai, CA

10.26.09

Begin by forgetting (or “unlearning”)  what you have been taught about light interaction with the retina and the  process of vision ( for example as heretical as it sounds, use of the terminology  “rods” and “color sensing cones”).  Completely start  over in your thinking even going so far as to examine what you really mean when you use the term “color” - it has been grossly misused as I will explain below.

Now…abstractly….the plane of retinal outer segments that everyone agrees is the plane where light is absorbed should be considered as no more than a circularly symmetric array of identical nanowires with incident light pervading  and completely filling the space between  them.

(Defining a “nanowire” - one might consider that this is the “central core” of  each individual retinal receptor or, alternatively, “the string of retinal molecules held within the rhodopsin protein structure that form the length of each  receptor”. It  is a space  of approximately 50 microns in length  (corresponding to the vertical dimension of an outer segment ) with a diameter of approximately ten nanometers  (or 10-8 meters) corresponding to the “quantum confinement dimension” of the electron.)

Light  incident on the retina is absorbed laterally from the surrounding space along the entirelength of each nanowire.

THIS IS THE CORRECT VIEW OF THE RETINA. Now unlearn all of the historically incorrect ideas about cones and rods and “photons interacting with pigments within receptors” and on and on……!

Moreover, in the above construction all nanowires in the array are identical. It is the dimensionality of the spaces between them that determines the light wavelength absorbed. And, this dimensionality geometrically dictates, as taught by this work, that three  and only three wavelengths are absorbed.

It should then be seen  that the nanostructure of the retina absorbs light as the wave of classical physics  in the space between nanowires with this absorption being necessarily adjacent to quantum spaces that corresponde to the electron absorbing mass. Each individual light detection site performs this fundamental physics transition.

There are thus two distinct steps in the process of light detection and vision. The first occurs at the point of the interaction of light with the plane of receptor outer segments. This step is effected in the quantum femtosecond  (10-15 sec) time domain. The  electronic signal used for subsequent processing  is generated at this step corresponding to the quantized electron generated from absorbed light energy. The subsequent processes in the “sub-retinal cicuitry”  of the retina serve to thermalize (or slow) the interaction to human nervous system proportion.

THE VISION PROCESS AT THE POINT OF INITIATION IS A QUANTUM PROCESS TRANSFORMING THE LIGHT WAVE  OF CLASSICAL PHYSICS TO A QUANTIZED ELECTRON PARTICLE AT EACH OF THE MILLIONS OF LIGHT DETECTION SITES ON THE RETINA.

The common identity of nanowires follows from the electron quantum-confining and retinal molecule that is ubiquitous to each one and that forms the endpoint of the light energy absorbing process. In traditional thought this molecule is known to be common to both cones and rods so there should be no problem in accepting this. These nanowires then are fundamental generic quantum-confined electron spaces that function as the “absorbing mass” of the light interaction process.

Imagining that each nanowire is the analogue of an optical fiber it has now been experimentally demonstrated (referenced in the body of the work)) that light flows around and not through the fiber when it’s diameter has been reduced to sub-optical wavelength dimension – as is the case here.

Wavelength absorbed by each nanowire is then controlled by the newly considered (this work) geometrical spacing of the array – and not as traditionally thought by “pigments”. The finding of this work that “an admixture of two spacings yields three specific spacings” then, consistent with the measured plan of the retina, verifies the trichromicity of the light interaction process of vision.

…but, crucially, the three wavelengths so absorbed DO NOT YET CONSTITUTE THE HUES OF COLOR! We have made a fatal  shortcut that “wavelength” and “color” are the same. The perception of color is the result of subsequent (to the initial retinal light interaction) processing of light intensities that fall on either side of the geometrically determined mid band point on the retina ACCORDING TO THE SEMINAL WORK OF EDWIN LAND.

Using an analogy pursued by Land (among others) color  represents the music and individual wavelength  interactions the underlying notes!

The true genius of Edwin Land never ceases to amaze me!

The chores of the day intrude and I will continue this shortly.

GCH

Ojai,CA

Disregarding  the facile quotes about the quantum such as Feynman’s “quantum physics deals with nature as she is—absurd”, I always remember what I thought was  Wolfgang Pauli’s truly meaningful  piece of insight that (paraphrased) “nature only answers when you ask the right questions.”

I have always been uneasy with the Schrodinger Cat paradox. I  certainly understood that  it  was an exercise contrasting the quantum and classical views of reality,  but  in the main I dismissed  my reservations as just a lack of  understanding on my part. Yesterday, however, I came upon an item in Economist.com that again attempts to describe the paradox and the thought occurred to me that, in the light of my work, does the paradox really ask the right question?.

The teaching of my work on light interaction with the retina of the eye demonstrates that there are two widely separated time domains operative in this interaction. These are: a) the fast “quantum-associated” time of the order of femtoeconds (10^-15 sec) or less that is consistent with  the experimentally demonstrated isomerization of the retinal molecules within receptors during the initial light interaction, and, b) thermalization of the absorbed energy in transit through the lipid membranous structure of the thylakoid disk that forms the body of the receptor, to a slower “biologically useful” time associated with biochemistry, nerve transmission etc.

Thus, two distinct times separated by perhaps thirteen orders of magnitude are involved in light interactiion with retinal outer segments “

I propose that these correspond to the separation of the classical and quantum view of physics and this classical/quantum interaction is effected at each of the millions of light detection sites on the retina. This is the function of the retinal nanostructure as I describe it.

How might all of this be associated with the Schrodinger’s Cat paradox? It occurs to me that two distinct time domains must be operative in the Schrodinger mental construction analogous to the proposal that I make defining a classical/quantum interaction (or transition) on the retinal surface. Separating …the first, accepted quantum nature of the radioactive decay process and, secondly, the slower (classical) nature of subsequent what must be termed classical actions – opening the box, movement of the hammer, etc.

It is obvious to me how this time separation is bridged in the light interaction with the nanostructure of the retina. How can the overtly-classical construction of the S. paradox ever bridge this time separation?

Are we asking the right question?

GCH

Ojai, CA

10.15.09

This explanation represents the first rational interpretation of the long accepted  (in every textbook) classical measurements of retinal morphology made by Osterberg in 1935 and clearly shows that the retina is a diffraction surface composed of three concentric rings of narrow wavelength response that correspond to the wavelengths that have been traditionally thought to be chromatic “aberrations”. This response represents the fundamental image-forming mechanism of the eye. There was never any discernible spatial ordering of “color-sensitive cones” on the retina that would indicate that this surface behaved as color film at the image plane of a camera - although this irrational model (i.e, not in consonance with any measurements) has been assumed for over a hundred years of vision science.

As I long ago noted, George Wald, who won the Nobel prize for his work on vision, clearly saw this in his experiments but the paper, Blue-Blindness in the Normal Fovea , has seemingly  received scant attention in the field. In the course of my work someone who should have known actually said to me: “Wald was a good experimentalist but…….). The foveal region then, that contains greater then 99% of all cones, is insensitive to blue, i.e., contains no “blue sensitive cones”. This is exact agreement with my explanation.

I’ll make this point inconspicuous by using a smaller font- but a diffractive surface shows that the retina forms the Fourier or focal plane of the eye. To form an image satisfying the Fourier equation, each light detection site on the retina must possess the ability to detect both the intensity and phase of received light. I have shown in this work how these sites are able to accomplish this.

See previous comments of mine to the point that the diffractive retinal surface is electromagnetically “tuned” to three precise wavelengths and that these wavelengths do not yet represent the sensation that we term “color”. They do represent, in this explanation, the precise ends (or limits at 400 and 700 nm), and, most importantly, the exact geometrically-defined center, i.e., at 550 nm, of the visual band*. One must think about this – the wavelength of light is associated with, or determined by, geometry in this biological system! And further, (see my “Rosetta Stone” diagram), a geometric construction of a mixture of two wavelengths determines an exact midband reference wavelength! Amazing!

* The presence of this fixed reference would seemingly explain the long standing unexplained conundrum of the “color constancy” of the vision process. See this link on the homepage where this is discussed.

It then becomes clear that the finally defined diffractive surface of the retina together with the unique finding of a precise mid band reference wavelength validates Edwin Land’s extensive model of color vision. Land termed this mid- band reference a “fulcrum” and to quote his words: “…we have learned that the eye must have a fantastic mechanism for finding a balance point within a band of wavelengths”. We have finally identified Land’s “fulcrum” – it lies at a retinal eccentricity of 8-9 degrees or, geometrically, where the density of smaller rod receptors is first sufficient to completely surround the remaining larger cones in octagonal symmetry*

* I believe, and have written about, there being further meaning to this symmetry).

The mechanism underlying Land’s model thus becomes clear. The sensation of color (or the “hues of color” or the point where the term color should first be used) is determined, as he proposed, by the eye defining the ratio of intensities (Land termed them “lightnesses”) on either side of the, now defined, fixed wavelength reference.

In my view, Edwin Land was the unheralded true genius in the history of vision!

GCH

Ojai, CA

10.02.09

Following from the concept of  “antennas” it should be obvious that the eye evolved to detect the wave of classical physics and not particle photons as is generally (and incorrectly) assumed.

The cone/cone appositions (i.e., the “center-to-center distance) in the fovea geometrically define the precise long wavelength limit of the visual band.  The cone/rod appositions that begin at the edge of the fovea and peak in number at 8-9 degrees of retinal angle define the precise, again geometrically-determined, center of the visual band. At larger retinal angles comprising the peripheral retina , rod/rod appositions define the, again precise, short wavelength limit of vision.

(it will  be obvious to those inclined to physics that the retina is structured as a diffractive surface and forms the Fourier or focal plane of the eye. The eye is not a camera! Each antenna/spatial light detection center possesses the ability to detect both the intensity and phase of light as required by the Fourier equation. I have proposed the retinal structure that accomplishes this in the main body of the paper)

The detection of these wavelengths at the plane of receptor outer segments occurs in the near field of the light wave and in very fast femtosecond time). At thiis point they are still “only wavelengths”.

As brilliantly shown by Edwin Land the sensation of the hues of color are then synthesized from what Land termed “lightnesses” (related to light intensities) on either side of the exact geometrically determined mid band wavelength (that this explanation defines!. It is only then that the term “primary colors” can be used.

The three wavelengths initially detected on the retina were always “primary” but not yet “color” !

How misleading this shortcut has been in the history of vision.

GCH
Ojai, CA
9.21.09

Further, and what has been confounding in past assumptions, is that the initial light interaction at individual  sites on the retina (that I define) lies within the near field of the light wave, i.e., within spatial dimensions smaller than the wavelength of light (approximately one micron),. This, in turn implies that the initial defining interaction occurs in the time domain approximating femtoseconds (or 10-15 seconds). These assumptions finally explain the ability of the eye to accomplish the feat of discerning single light photons (or, as defined above, “single quantized interactions”)at body temperature.

There is a significant amount of modern experimental results (thoroughly referenced in the body of the work) that supports this explanation. These include recent experimental results showing that light travels outside of optical fibers that are smaller in diameter than light wavelength and the long known experimental result that the signal-forming isomerization of the retinal molecule (within the rhodopsin structural protein complex) occurs in femtosecond time. These results taken together support this new explanation.

I must emphasize that all of the foregoing applies to the initial  light interaction at the plane of the outer segments of each individual retinal center. The electron particle that results is actually “thermalized” in the absorption process for subsequent use in the biochemical processes of the remainder of the retina . I believe that  thermalization follows from the transit of the absorbed energy along the length of the membrane of each thylakoid disk that forms the length of the receptor outer segment.

The traditionally taught  model that that the eye functions as a “camera” in slow time of  the order of  milliseconds (10-3 second) must be abandoned.

The future of vision research is inexorably bound up with the considerations and evolution of quantum physics.

A note:

I believe that seminal thoughts in this regard are contained in a recently published paper by Engel et al of the University of California at Berkeley.
(Evidence for Wavelike Energy Transfer Through Quantum Coherence in Photosynthetic Systems”).This group using new femtosecond spectroscopy  observes quantum coherence (or “quantum wave-like” behavior) within the near field of light and in femtosecond time. I must add that I have proposed and written that the same light interaction mechanism of this work explains the extraordinarily high light detection efficiency of photosynthesis as well as the ability of the eye to see single quanta.

Written on a quiet Sunday morning in Tucson, AZ !

GCH
9.13.09

From the section: Vision of the Trichromat on p.179,   following the previous and  correct insights of Young, Helmholtz et al describing  the trichromicity of visual response:

“In the case of trichromat vision the situation is more complicated, but it can be said with logical certainty that the trichromats must possess at least three kinds of cones…….”.

(I am reminded here of a comment made years ago by a friend of mine about a colleague of his that “he was the most logical individual he had ever known but he was invariably wrong!)

I propose that the “logical certainty” argument of the statement arrives at an erroneous conclusion -    it is not three kinds of light detecting “cones”, but really three kinds of  light detection “centers”. In this work these centers are shown to be receptor appositions and not the cone or rod receptors themselves…..with, further, the organization of these centers demonstrating that the retina is a diffractive surface……..further still indicating clearly that the retina forms the Fourier (or focal) plane of the optics of the eye…….and on.

Light does not interact within receptors but between adjacent receptors.

The protein opsin within the receptors themselves plays a structural role in holding the retinal molecule - that is ubiquitous to all receptors  - in the three (cone/cone, cone/rod, and rod/rod) light-accepting conformations.

Each of these individual light detection centers functions in what is termed the “near field” of  light wavelength, i.e., in the spatial domain less than one micron. (in the fiberoptics analogy this means that light  travels on the outside of a receptor/fiber)

In turn, the speed of the light detection process is extremely fast - in the femtosecond (or 10-15 sec)  time domain.

There can be no doubt that the eye evolved to detect (interact with) the wave nature of light.

It was never that “photons…interact with pigments within receptors etc.) and the ensuing, nonsensical, “photon catch” hypothesis!

The process of quantization of light is effected at each of the hundreds of millions of light detection sites on the retina  where the light wave is translated into a quantized electron particle.

The retina is a truly unique nanostructural array!

GCH
9.05.09

To wit:

1. As described in this work, the retina of the eye evolved to interact with the electromagnetic radiation that we term “light” as a wave and not, as historically assumed, as “photons interacting with pigment molecules within receptors”. Although the visual band is described as extending from 400 to 700 nanometers we need not  at all be concerned with these numbers! The retina has been evolutionarily “tuned” following the principles of this work, to only three narrow wavelengths that define the precise endpoints, and, importantly to what follows, the exact middle of this band. We need not concern ourselves with any “laboratory numbers”- nature employs pure geometry to determine these values. This view is in consonance with, and is the basis for,  the accepted “trichromicity” of vision that was correctly deduced long ago by Young. BUT….following this correct deduction, it was imagined that there were three “primary” (that much is correct - they are “primary”)) but then followed by the term “colors” to which the retina was supposedly sensitive. IT IS CRUCIAL THAT IT BEEN SEEN THAT AT THIS POINT ON THE RETINA THIS IS NOT YET COLOR!

2. In the broadest sense,  we should realize that the sensation that we have come to know as “color” (that might more properly be understood as  “the many hues of color”) must be differentiated from the three narrow “primary  wavelengths” that the retina detects - that  at this point have not yet been synthesized into “colors”. Moreover, it becomes clear from this work that the geometrical basis for light interaction (summarized above) finally explains how the sensation of  color  (”the hues of color”) is  synthesized and  validates the prescient work of Edwin Land!  Land, without any knowledge of of this geometric model of light interaction on the retina, reasoned that, what he termed a “fulcrum”, existed somewhere in the vision process that divided the visual band. It is now known that this fulcrum dividing point is determined by the geometrically defined mid-band (I will use numbers - 550 nanometers) centers corresponding to cone-to-rod appositions. Land found that (again the “sensation” of ) color, was determined by  the eye determining a ratio of  what he termed “lightnesses” (roughly light intensities) on either side of this defined fulcrum on the retina. It becomes clearer that Edwin Land was the true genius of vision science! Differentiate the three primary wavelengths that the retina detects and the following synthesis of the sensation of color

Respectfully submitted,

GCH Ojai, CA 9.03.09

I could not, and  still do not, understand how the vision field could reconcile this random distribution of light detection centers (or pixels) with any logical image-forming process!

(Incidentally, I do in this work  reconcile the distribution of receptors with an image-forming process explaining directly from Osterberg’s  historic retinal topology measurements, without any doubt, that the retina is the Fourier (or focal) plane of the eye with each pixel having the  necessary capability for processing both the intensity and phase of incoming light as the Fourier equation demands).

So, a dilemma -  the historically found statistical distribution versus the  logical requirement for some sort of ordered array of receptors?  ( and I didn’t even mention that in  measurements of the statistical distribution of “color sensing” receptors there is always a paucity of blue sensitive things - blue cones are very difficult to find! All of this is explained in this work.

Examples of recent work demonstrating  the statistical distribution of receptors are  the experiments of Roorda et al that I have previously referenced.(over and over!)  This group developed a method for microscopically imaging and identifying  individual retinal receptors. Their initial measurements focused on a region of the retina near one degree of eccentricity. This is a transition region where the density of cones is rapidly decreasing and where the introduction of rods is rapidly taking place . The rods being introduced crowd and fill  the spaces between the  diminishing  number of cones. (it is the statistically small number of rod-to-rod appositions that form “blue” centers that are misrepresented as cones). In summary, the centers defined as cones in this region was totally random.

(I would be derelict in my duty if I did not insert here the thought that what they found was in exact accord with my explanation! Their “red-sensitive” cones were actually cone/cone apposition centers that were still dominant in this region. What they termed “green sensitive” cones were cone/rod appositions that were beginning to statistically appear. The few (very few!) centers that they labeled “blue sensitive” were the small number of rod/rod appositions. All is geometry!).

One can read in my preceding Comments on this page where I repeatedly suggested that if the Roorda group, or some other group using their methods,  would make the same type of measurement at  a larger retina angle - near 8 degrees of eccentricity - they would find that, in their terms, “green cones” would predominate. I heard no direct acknowledgement  to my request but another group ( 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) did make such measurements at larger retinal eccentricities. They reported  (surprisingly!) finding what they chose to term  a “clumping” of green cones in this region - in accord with what I had predicted although there was no acknowledgment of this.

This second group, apparently still seeking some spatial order buried in the random distribution, employed statistical sampling tests to locate some degree of order. -They found  none (other then the “clumping of green cones”).

In this work  the only spatial order of the retina  is  contained in the three diffractive regions  (the long wavelength limit, the exact geometrically defined midband wavelength, and the short wavelength limit).  I had assumed that these regions were circularly symmetric on the retinal surface.  I recently came upon something, however, that indicates that perhaps there may be a larger “over-arching” order to retinal structure.

In reading “THE GOLDEN RATIO” by Mario Livio (published in 2002 by Random House) about this fascinating number (1.618…..),  the author introduces the  “Wonderful (or logarithmic) Spiral”. I’ll not go into this (one can read the book), but looking at the structure of the head of a sunflower that displays such a spiral (p.36) I remembered a plate from Pirenne (VISION AND THE EYE), specifically Plate 7. This figure from a drawing by Schultz in 1866 (!) is titled the “mosaic of the cones in the fovea centralis of human retina” and is abstracted in the following:

There is certainly a spiral motif when viewed from this larger perspective.

GCH

Ojai, CA

8.25.08

From Wikipdia on the sbject of Phyllotaxis and Physics - the “Wonderful Spiral” in biology”

“Physical models of Phyllotaxis date back to Airy’s experiment of packing of hard spheres. Douady et al. also have shown experimentally and theoretically that phyllotactic patterns
emerge as self-organizing processes in dynamic systems.[4] In 1991, Levitov proposed that lowest energy configurations of repulsive particles in cylindrical geometries reproduce the spirals of botanical phyllotaxis.[5] More recently (2009), Nisoli, Gabor et al. have shown experimentally and numerically that indeed that was the case, by constructing a “magnetic cactus” made of magnetic dipoles mounted on bearings stacked along a “stem”.[6] They also revealed that these interacting particles can access novel dynamical phenomena beyond what botany yields: a family of highly non local novel topological solitons emerge in the nonlinear regime of these systems, as well as purely classical rotons an maxons in the spectrum of linear excitations. They named these novel phenomena “Dynamical Phyllotaxis”, as they appear in physical systems whose statics is dictated by the number theoretical laws of Phyllotaxis.”