What is the role of the lens in vision?

• A. To protect the retina from light damage.
• B. To refract light rays and focus them on the retina.
• C. To regulate tear production.
• D. To detect color.

Answer: (B)

The lens refracts light rays and focuses them on the retina. Light is bent mainly by the cornea, but the lens provides the fine-tuning and adjustable focusing needed for clear vision at different distances. By changing its shape through accommodation, the lens becomes more curved to focus nearby objects and flattens to keep distant objects sharp. This ability to adjust focal length ensures that images land on the retina rather than behind or in front of it. The other options describe functions not performed by the lens: protecting the retina from light damage involves other structures like eyelids and the pupil’s regulation of light, tear production is controlled by the lacrimal system, and color detection occurs in retinal cones, not in the lens.