What does the pupil do?

The pupil is an essential part of the eye that directly influences how much light reaches the retina, which is vital for clear vision. It does this by adjusting its size in response to the brightness of the surrounding environment. In bright light conditions, the pupil constricts to limit the amount of light entering the eye, protecting the sensitive retina and helping to maintain optimal vision. In dim lighting, the pupil dilates, allowing more light to enter, which enhances visibility in low-light situations. This regulation of light is crucial for facilitating the best possible vision across different lighting conditions.