Which part of the eye is primarily responsible for refracting light?

The cornea is primarily responsible for refracting light in the eye. It is the clear, dome-shaped surface that covers the front of the eye and provides most of the eye's optical power. The cornea bends incoming light rays, directing them toward the retina, where they are focused to create an image. Its curvature and the refractive index play crucial roles in determining how well light is focused.

While the lens also contributes to refraction by fine-tuning the focus of light onto the retina, it is the cornea that does the majority of the bending of light as it enters the eye. The iris and pupil have different functions; the iris controls the amount of light entering the eye by adjusting the size of the pupil, while the pupil is simply the opening that allows light to pass through to the retina. Therefore, identifying the cornea as the main structure responsible for light refraction highlights its essential role in vision.