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.Arguably, it may increase the depth of field by reducing the aperture of the eye, and thus reduce the amount of accommodation needed to bring the image in focus on the retina.
The dependency of accommodation amplitude on age is graphically summarized by Duane's classical curves.
Lillian: I moved here in the Blue Mountains which is little bit past Sydney.
I decided to move to Wollongong because it offered the best course for me, but I really didn't want to be traveling back and forth. Ally: I thought that it would be so far from everything, but the train station is so close whenever something is happening in Sydney, I just jump on the train.
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).
The combination of these three movements (accommodation, convergence and miosis) is under the control of the Edinger-Westphal nucleus and is referred to as the near triad, or accommodation reflex.