Question

which structure in the eye refracts light first? lens cornea retina sclera

Explanation:

The cornea is the clear front part of the eye that covers the iris, pupil, and anterior chamber. It refracts light as it enters the eye, providing most of the eye's focusing power. The lens further refines the focus, but the cornea is the first structure to refract light. The retina is where the image is formed (it does not refract light first), and the sclera is the tough outer coat of the eye (not involved in refracting light).

Answer:

Cornea