What is the purpose of a lens in eyeglasses?

The purpose of a lens in eyeglasses is primarily to correct vision by focusing light properly on the retina. When light enters the eye, it must be focused accurately on the retina for clear vision. For individuals with refractive errors, such as myopia (nearsightedness) or hyperopia (farsightedness), the natural lens of the eye does not refract light correctly. Eyeglass lenses are designed specifically to correct these refractive errors by bending light rays in a way that ensures they converge on the retina, allowing for clear images.

The design and curvature of these lenses can vary depending on the specific needs of the wearer, helping to ensure that they can see clearly at various distances. This correction is essential for good vision, enabling the eye to perform its function effectively.

The other options relate to functions that are not the primary purpose of eyeglass lenses. For instance, filtering colors or magnifying objects does not address the fundamental need for clear image formation on the retina. Additionally, while some lenses may provide protection from UV rays, this is not their primary corrective function for vision.