What part of the eye is responsible for adjusting light intensity through dilation and constriction?

The iris is the part of the eye that is responsible for adjusting light intensity through dilation and constriction. It is a thin, circular structure located behind the cornea and in front of the lens, containing muscles that control its size. When the light intensity is low, the iris dilates (enlarges) to allow more light to enter the eye, helping to improve visibility. Conversely, in bright conditions, the iris constricts (shrinks) to reduce the amount of light entering the eye, protecting the retina from potential damage and aiding in clearer vision.

This dynamic control enables the eye to adapt to varying lighting conditions, enhancing the visual experience. Other parts of the eye, such as the cornea, lens, and sclera, do not have this specific function of adjusting light intensity; rather, they have different roles in focusing light and maintaining the structure of the eye.