The term is sometimes used incorrectly to refer to the amplitude of accommodation without the influence of the depth of focus (e.g. See subjective accommodation; optometer; evoked cortical potential; dynamic retinoscopy; stigmatoscopy.ocular accommodation The amplitude of accommodation referred to the front surface of the cornea. See spectacle accommodation.open-loop accommodation Accommodative response occurring without the usual stimulus to accommodation, such as a blurred retinal image.In these conditions, the accommodative system of the eye tends to return to its position of rest (or tonic accommodation).See myopic defocus.mechanism of accommodation Process by which the eye focuses onto an object.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.
So, if the near point of an emmetrope is at 25 cm from the spectacle plane, the amplitude of accommodation is equal to − [−1/(25 ✕ 10)] = 4 D.
Contact lenses do not induce any different accommodation than that required for a given distance.
Consequently, myopes require more accommodation and hyperopes less accommodation when they transfer from spectacles to contact lenses.
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.
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. In accommodation for near vision, the ciliary muscle contracts, causing increased rounding of the lens, the pupil contracts, and the optic axes converge.