Which structure bends (refracts) light to focus it on the retina?

Which structure bends (refracts) light to focus it on the retina?

• A. Lens
• B. Cornea
• C. Iris
• D. Pupil

Answer: (A)

Light is refracted by two surfaces in the eye, with the lens serving as the adjustable focusing element. The lens changes shape through accommodation, becoming thicker to increase refractive power for near objects and thinner for distant ones, so incoming light rays are bent precisely to converge on the retina. The cornea does most of the initial bending, but the lens fine-tunes the focus to produce a sharp image. The iris and pupil regulate how much light enters, not how the light is focused.

Light is refracted by two surfaces in the eye, with the lens serving as the adjustable focusing element. The lens changes shape through accommodation, becoming thicker to increase refractive power for near objects and thinner for distant ones, so incoming light rays are bent precisely to converge on the retina. The cornea does most of the initial bending, but the lens fine-tunes the focus to produce a sharp image. The iris and pupil regulate how much light enters, not how the light is focused.