Final answer:
The lens focuses light on the photoreceptor cells by changing shape through a process known as accommodation. The muscles around the lens alter its curvature to focus light sharply on the retina, which contains photoreceptor cells that send visual information to the brain.
Step-by-step explanation:
The lens focuses light on the photoreceptor cells by changing shape. The process, known as accommodation, is crucial for our eyes to focus light correctly on the retina from objects at various distances.
Muscles connected to the lens adjust its curvature, altering the focal length to allow the eye to focus on both near and far objects. This action ensures that images are projected onto the retina, where photoreceptor cells, rods and cones, detect light and initiate nerve impulses that travel to the brain via the optic nerve.
The pupil, controlled by the iris, dilates and constricts to regulate the amount of light entering the eye, but does not play a direct role in focusing light on the retina. In conditions such as nearsightedness and farsightedness, corrective lenses are used to adjust the optical power of the eye, thereby enabling clear vision by correctly focusing light on the retina.