Which part of the eye is responsible for focusing light on the retina?

The lens is the part of the eye that is responsible for focusing light onto the retina. Located behind the iris and pupil, the lens is a transparent, flexible structure that alters its shape to adjust the focus of light entering the eye. This ability to change shape, through a process known as accommodation, allows the lens to fine-tune the focus for objects at various distances. When light enters the eye, it first passes through the cornea, which contributes to the initial bending of the light rays but is not solely responsible for focal adjustments. The light then travels through the pupil and arrives at the lens, where it is precisely focused onto the retina, allowing for clear vision.

The other components mentioned play important roles in vision but do not directly focus light. The iris controls the size of the pupil and thus the amount of light entering the eye, while the cornea contributes to overall light refraction but not the adjustable focus needed for clear vision.