When we think of our eyes, we often think of them as windows to the soul. They let us see the world around us and can reveal emotions such as joy, sadness, and fear. But have you ever wondered how they work? Specifically, do the pupils or irises contract? Let`s explore this question further.

First, let`s define some terms. The pupil is the small, black circular opening in the center of the iris. The iris is the colored part of the eye that surrounds the pupil. The iris is responsible for controlling the size of the pupil, which in turn controls the amount of light that enters the eye.

So, to answer the question at hand: both the pupil and iris contract. The pupil contracts in response to bright light and dilates (becomes larger) in response to dim light. This is because the amount of light entering the eye needs to be regulated to maintain clear vision. The iris is responsible for this regulation by controlling the size of the pupil.

But how does this happen? The iris is made up of two sets of muscles: the circular muscles and the radial muscles. The circular muscles encircle the pupil and contract in response to bright light, causing the pupil to constrict (become smaller). The radial muscles extend from the center of the iris to the outer edge and contract in response to dim light, causing the pupil to dilate.

This process is automatic and happens without our conscious control. However, certain drugs and medications can affect the size of the pupil and cause it to remain dilated or constricted for longer periods of time.

In summary, both the pupil and iris contract in response to changes in light to maintain clear vision. The iris controls the size of the pupil through the circular and radial muscles. Understanding how our eyes work can help us better appreciate and take care of them.