What does a lens primarily do in the context of vision?

A lens in the context of vision primarily functions to focus light onto the retina, which is essential for clear sight. When light enters the eye, it passes through the lens after traveling through the cornea. The lens bends or refracts the incoming light rays to concentrate them precisely on the retina at the back of the eye. This focused light is crucial for the brain to create a clear image. The retina then converts this focused light into electrical signals that transmit visual information to the brain, allowing us to see.

Focusing light ensures that the images we perceive are sharp and in focus. If the lens fails to focus light correctly, it can result in vision problems such as myopia (nearsightedness) or hyperopia (farsightedness).