What is the opening or hole in the center of the iris of the eye called?

The opening or hole in the center of the iris of the eye is known as the pupil. Its primary function is to regulate the amount of light that enters the eye, adjusting in size depending on lighting conditions. In bright light, the pupil constricts to limit the light intake and protect the retina, while in dim light, it dilates to allow more light to enter, enhancing visibility. This dynamic adjustment plays a crucial role in maintaining optimal vision performance under varying environmental conditions. The iris surrounds the pupil and is responsible for its color, which can vary widely among individuals. Understanding the function and structure of the pupil is fundamental in the study of eye anatomy and physiology.