Final answer:
The lens in the human eye refracts light by bending it towards a focal point on the retina. The convex shape and higher refractive index of the lens allow it to adjust and focus light from different distances, ensuring clear vision.
Step-by-step explanation:
The human eye contains a convex lens which is responsible for focusing light onto the retina. When light enters the eye, it passes through the cornea and then through the lens, which has a higher refractive index compared to the air. According to the law of refraction, as light hits the curved surface of the lens, it is bent towards the perpendicular to the surface at both the point of entry into the lens and the point of exit from the lens.
The lens's convex shape causes light rays to converge at a single focal point behind it, where the image is formed. This focusing ability of the lens allows it to bring light from objects at various distances into a clear focus on the retina, an essential function for vision. The lens is able to change its shape, or accommodating, to focus light from objects that are both near and far, ensuring that the images on the retina are as sharp as possible.