defocus

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defocus

(de-fo'kus) [L. de, away from, + focus, hearth]
The blurring of a visual image caused by spherical aberration, chromatic aberration, or diffraction. Also called optical defocus. Synonym: optical defocus

optical defocus

Defocus.

defocus

To put or go out of focus.
hyperopic defocus State of the eye in which the retinal image is focused behind the retina. It may occur when placing a negative lens in front of an emmetropic presbyopic eye; in an uncorrected presbyopic hyperope; in a high hyperope unable to overcome the ametropia by accommodating; or as an accommodative lag in an uncorrected or corrected myope, as well as in an emmetrope viewing a near object. See lag of accommodation; over-correction.
myopic defocus State of the eye in which the retinal image is focused in front of the retina. It may occur when placing a positive lens in front of an emmetropic eye; in an uncorrected or undercorrected myopic eye; or if there is a lead of accommodation, as is the case in some individuals viewing a distant object. See lead of accommodation; under-correction.