What is the purpose of the lens in the eye?

The lens in the eye serves a critical role in vision by focusing light onto the retina. When light enters the eye, it first passes through the cornea and then the lens. The lens adjusts its shape—through a process called accommodation—to appropriately bend the incoming light rays so that they converge on the retina, which is the layer of photoreceptor cells that captures the light and begins the visual processing. This precise focusing is essential for clear vision, enabling us to see objects both near and far distinctly.

In contrast, while some parts of the eye do help absorb excess light and protect internal components, the primary function of the lens is specifically focused on the refraction of light to create a clear image on the retina. The stabilization of the eye's shape is primarily the role of the sclera and intraocular pressure rather than the lens itself. Thus, the lens's main function is crucial for achieving optimal visual clarity, making "to focus light onto the retina" the correct answer.