Accommodation usually acts like a reflex, including as part of the accommodation-vergence reflex, but it can also be consciously controlled.
Mammals, birds and reptiles vary the optical power by changing the form of the elastic lens using the ciliary body (in humans up to 15 dioptres).
When humans accommodate to a near object, they also converge their eyes and, as a result, constrict their pupils.
However, the constriction of the pupils is not part of the process called lens accommodation.
A near object (for example, a computer screen) appears large in the field of vision, and the eye receives light from wide angles.
When moving focus from a distant to a near object, the eyes converge.
This process can occur in as little as 224 ± 30 milliseconds in bright light . By the fifth decade of life the accommodative amplitude can decline so that the near point of the eye is more remote than the reading distance. Once presbyopia occurs, those who are emmetropic (do not require optical correction for distance vision) will need an optical aid for near vision; those who are myopic (nearsighted and require an optical correction for distance vision), will find that they see better at near without their distance correction; and those who are hyperopic (farsighted) will find that they may need a correction for both distance and near vision.
She is the author of The Everything Parent’s Guide to Special Education.
Or maybe you want to build up credit for accommodating that you might use later.
(This technique can backfire if you end up with a reputation for not standing your ground.
Accommodation is the process by which the vertebrate eye changes optical power to maintain a clear image or focus on an object as its distance varies.
In this, distances vary for individuals from the far point—the maximum distance from the eye for which a clear image of an object can be seen, to the near point—the minimum distance for a clear image.