How does the optical system of the eye adapt to the perception of objects at different distances?

The optical system of the eye is often compared to the optical system of a camera. It consists of the following elements:

cornea;
Iris;
lens;
retina.
The lens functions as a lens in the optical system of the eye. It is a transparent body, similar in shape to a biconvex lens. The muscles surrounding the lens are able to change its curvature, and thus the focal length, that is, the distance from the center of the lens to the retina.

The ability of the optical system of the eye to change the focal length is called accommodation. It is she who provides the eye with adaptation to the perception of objects at different distances.