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The effect of defocus on the contrast and phase of the retinal image of a sinusoidal grating
Author(s) -
Walsh G.,
Charman W. N.
Publication year - 1989
Publication title -
ophthalmic and physiological optics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.147
H-Index - 66
eISSN - 1475-1313
pISSN - 0275-5408
DOI - 10.1111/j.1475-1313.1989.tb00941.x
Subject(s) - optics , spatial frequency , accommodation , wavefront , contrast (vision) , retinal , grating , physics , pupil , image contrast , computer science , ophthalmology , medicine
The variation with defocus in the contrast and phase of the retinal image of a grating stimulus is computed from a knowledge of the meaured wavefront aberration of individual eyes. Contrast or modulation transfer is generally lower than in the aberration‐free, diffraction‐limited case, even at a pupil size of 3 mm, and marked spatial phase shifts, which can be seen as sideways shifts in the retinal image, frequently occur. A simple demonstration of these effects is given. The possible significance of the focus‐dependent spatial phase shifts for the phase discrimination of the visual system and accommodation is discussed.