THIS FIGURE WAS PUBLISHED IN 1866– (MY INTERPRETATION IS REALLY NOT TOO DIFFICULT TO UNDERSTAND !)

The following drawing is from Pirenne’s Vision and the Eye (Plate 6 of the Second Edition). The original reference for this drawing as noted by Pirenne is: Schultz (1866), Arch. mikr. Anat., 2, 175). Note the date of this reference!

The Title of Plate 6:

“The mosaic of rods and cones in various regions of the human retina, as seen under the microscope in fresh preparation”.

The figure reproduced here is one of three drawings in the plate and is labeled “Close to the yellow spot” (with others labeled “Periphery” and “At the ora serrata”).

This is a very important figure.

This is the distinct retinal motif that occurs at between eight and nine degrees of retinal eccentricity (as measured from the fovea) and is the point where the density of rods is first sufficient to completely surround each cone. This is the only point on the retina where this motif occurs.

An octagonal “eight rods around one cone” structure is seen.

Please note that the only geometric construction that can result in this symmetry is a ratio of 1.8:1 which is the actual ratio of sizes of cones to rods and which additionally corresponds to the visible band – 700-400 nanometers!

Thus it is the ratio of the sizes of the two types of retinal receptors that geometrically determines the width of the visible band.

It follows that the absolute size of individual receptors determines the wavelength range detected – it has been well documented that the ultraviolet vision birds have smaller receptors etc.

Now onto important matters.

From the Rosetta Stone diagram of the original paper reproduced below, the center-to-center distance between the cone and rod receptors geometrically determines the exact midpoint of the visible band of wavelengths. Please let this point sink in!

This point represents a geometrically-defined midband point from which all other wavelengths are referenced in determining the sensations that we term color (as Edwin Land brilliantly defined).

It also follows that two sizes of receptors  creating such a midband reference must be present on the retina for the sensation of color to be perceived.

It is seen then that geometry and electromagnetic wavelength are inexorably linked. It occurs to me that I am actually defining, what at longer wavelengths, is termed an “antenna”!

It follows that “optical wavelength antennas” exist – which returns to the point where this entire exercise began!

This light interaction on the retina at 8-9 degrees represents the peak of response to the middle (we term in shorthand “green”) the wavelengths that have been termed “primary”. This point (motif) is precisely “tuned” to this single wavelength with the density of octagonal structures leading to the claim that it is the peak of response.

Notes:

a.) The notation for the figure by Pirenne states that the referenced figure is taken “somewhere near the yellow spot”. The connotation of yellow is vague in the literature referring to the macula that may have something to do with the yellow lutein molecule present in the eye. I have proposed that formation of lutein in the eye may represent a “second line of defense” in preventing overexposure to light and damage to the retina.

b.) Crucial……as noted by Snyder (referenced in the original paper) the octagonal motif of the human retina seems to be characteristics of all species from crustaceans to honeybees. Meaning..??

GCH

11.10.09

Ojai,CA