defocus

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defocus

[dē′fō·kəs]
(engineering)
To make a beam of x-rays, electrons, light, or other radiation deviate from an accurate focus at the intended viewing or working surface.
References in periodicals archive ?
TRV can be influenced by a number of factors and has been shown to increase in the presence of optical defocus, (13) and ocular pathology.
Because optical defocus selectively attenuates the contrast of higher spatial frequencies, older adults appear to be generally superior to younger ones in using residual low-spatial-frequency information to identify blurred text.