In middle age PRESBYOPIA becomes apparent in all but the near-sighted. It is generally involuntary and made to see objects clearly at any distance.In man (and primates), this adjustment is brought about by a change in the shape of the crystalline lens.In some animals this adjustment occurs either as a result of an anteroposterior movement of the crystalline lens, or of an alteration in the curvature of the cornea.
Accomodating children video
These three actions constitute the accommodation reflex.
The ability of the eye to accommodate decreases with age.
Synonym: ocular accommodation; visual accommodation See: illustration4.
Changes during accommodation: (A), contraction of ciliary muscles; (B), approximation of ciliary muscles to lens; (C), relaxation of suspensory ligament; (D), increased curvature of anterior surface of lens.4 (in sociology) the reciprocal reconciliation of conflicts between individuals or groups concerning habits and customs, usually through a process of compromise, arbitration, or negotiation. Occupational medicine The changes made by a person or organisation to a workplace to allow a person with disabilities to work there.
Fringe ophthalmology Near and far focusing—an exercise in Bates vision training, which consists of changing the point of focus from near to far distances multiple times.
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.
In the learning theory of Jean Piaget, the process through which a person's schema of understanding incorporates new experiences that do not fit existing ways of understanding the world.
See: adaptation The automatic process by which the eyes adjust their focus when the gaze is shifted from one point to another at a different distance.
Accommodation is achieved by changing the degree of curvature of the internal crystalline lenses of the eyes.
In youth, these are naturally elastic and become more curved when the pull on the ligament by which they are suspended is reduced by contraction of the surrounding muscle ring (CILIARY MUSCLE). The elasticity of the lenses drops progressively with age so the power of accommodation lessens.