It does so by contracting the ciliary muscle which releases the tension on the zonular fibres, allowing the elastic lens capsule to increase its curvature, especially that of the front surface.
Along with these changes are an increase in the thickness of the lens, a decrease in its equatorial diameter and a reduction in pupil size.
In man (and primates), this adjustment is brought about by a change in the shape of the crystalline lens.
The ciliary muscle is controlled by the parasympathetic system, which is triggered by an out of focus retinal image. See push-up method; near point rule; near point sphere; Scheiner's test.negative accommodation 1.
See convergence accommodation; proximal accommodation; accommodative response; ciliary muscle; near reflex.meridional accommodation See astigmatic accommodation.microfluctuations of accommodation Involuntary variations in the contraction of the intraocular muscles responsible for accommodation and resulting in changes of about 0.1-0.5 D with a frequency of 0.5-2.5 point of accommodation The nearest point in space that is conjugate with the foveola when exerting the maximum accommodative effort. A relaxation of accommodation below the apparent zero level or when shifting from near to distance vision. See relative amplitude of accommodation.objective accommodation Accommodation measured without the subject's judgment.
Ophthalmology The automatic adjustment of the lens curvature, resulting in a change in the focal length of the eye, which brings images of objects from various distances into focus on the retina; the ability of the eye to focus at various distances, by changing lens shape.
Psychology In Piaget's theory of cognitive development, the change that occurs in an existing mental scheme or set of schemes due to assimilation of the experience of a new event or object. The adjustment of the eye for various distances whereby it is able to focus the image of an object on the retina by changing the curvature of the lens.
Absence of an accommodative lag may indicate latent hyperopia. It can also occur as a result of a spasm of accommodation.