A curved piece of glass used to refract light; the flexible structure that focuses light entering the eye is the

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

Answer: (C)

Focusing light is the job of a lens. The lens in your eye is a flexible, curved structure that can change its shape to adjust how strongly it bends light, so images land sharply on the retina. Light first passes through the cornea, which does most of the initial bending, but the lens fine-tunes focus for objects at different distances through a process called accommodation, enabled by the ciliary muscles.

The iris is the colored part that controls how much light enters by changing the pupil size, not by focusing. The retina is the light-detecting layer at the back of the eye where the focused image is formed, not where the light is bent to focus.