The explanation of color vision based on fiber coupler theory of foveal cones

In this paper, we first propose that there is strong optical coupling between the two outer-fibers and inner segments of two adjacent foveal cones, and our simulation proves our new fiber coupler theory of foveal cones. This is the first discovery of fiber couplers in biological bodies. It is found that a red and a green light exchange energy almost completely between two adjacent cones; the most of the energy of a yellow light couples into the adjacent cone’s outer- segment. However, the energy of a blue light is divided equally into two parts in the two adjacent cones’ outer-segments approximately. By using the optical coupler theory, we unify the two important color vision theories (the trichromatic theory of vision and the opponent color theory), which have been controversial over 138 years. We find the anatomic basis of the opponent color theory on the retina photoreceptor level, and we solve this world class difficult problem lasting for 138 years. When a light enters the outer fiber and inner segment of adjacent cones, the wavelength dependent optical coupling occurs. We call the strong optical coupling region as the color preprocessing stage. By adding the color preprocessing stage, we first propose the four stage theory for color vision based on the traditional three stages (stage theory). According to our new discovery on the crossover behavior of red and green light in the two neighbor red and green cones, we first propose that an erect image is formed in the two neighbor foveal cones’ outer-segments where the photoelectric conversion processes, and this new phenomena overturns the traditional knowledge of that an inverted image is formed in the two neighbor foveal cones’ outer-segments. Finally, by considering the blue light behavior in the coupling process, we propose that the reason for the absence of S-cones in the very central region (15′ blue blinded region) of the central fovea is to increase the spatial resolution.