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A retinal 3D grating chip in the focal plane of the lens/pupil system of the human eye explains phenomena which are dependent on the aperture or degree of coherence (Stiles-Crawford effects I and II). It thus simultaneously explains how the eye deals with phase information. Interpretation of the retina (positioned lightward of the photoreceptors) as a cellular 3D grating chip with hexa- gonal closest packing geometry of the cell nuclei which, as a phase grating, is positioned in the focal plane of the lens/pupil system (2) allows the Stiles-Crawford effects I and II, which are dependent on the aperture or degree of coherence, to be calculated via the classical von Laue formula of crystal optics with 3 interference terms. These effects prove to be two aspects of a single multilayer grating optical effect in human vision. They also show how the eye deals with the phase information in partially coherent light: aperture-related phase shifts are transformed into brightness shifts (SCE I) and hue shifts (SCE II) which can be detected in the Fresnel near field behind the retina, ie. in the outer segment disks of the cones, which in photopic vision are positioned at the trichromatically differen- tiated, concentric locations of the interference maxima. The calculated data shown here relate exclusively to mono- chromatic test lights in the visible spectrum (400 - 800 nm) incident obliquely on the pupil and retina against an equienergy white background, as for the comparative experimental SCE II data obtained by Enoch and Stiles (1). The SCE II is an aperture-dependent hue shift in the vector field of the phase velocity, while the SCE I is a corresponding brightness shift. The von Laue formula is as follows on the basis of the three fundamental conditions for constructive interference:
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