Which eye structure is primarily responsible for bending light to focus images?

The primary structures responsible for bending light to focus images on the retina are both the cornea and the lens. The cornea, which is the eye's outermost layer, is the first point of contact for light entering the eye and provides most of the eye’s total optical power. It has a fixed curvature and helps to refract, or bend, light rays.

The lens, located behind the iris and the pupil, further fine-tunes the focus of the light rays. Unlike the cornea, the lens can change shape due to the action of the ciliary muscles surrounding it. This flexibility allows the lens to adjust focus for objects at varying distances, a process known as accommodation.

Together, the cornea and lens work in tandem to ensure that light rays are correctly focused onto the retina, allowing for clear vision. Thus, acknowledging the roles of both structures in the focusing process leads to the understanding that they collectively contribute to the eye's ability to form images.