The pupil of the eye is a black circle in the middle of the iris. Iris is a colorful ring in the eye with color and structure unique to each person. From the outside of the eye, the light passes through the transparent lens and then through the pupil. When the light reaches the tissues in the back of the eye, it is absorbed, making the pupil look black.
The purpose of the iris and pupil function is to control the amount of light reaching the eye. This is called pupillary reflex and you probably noticed that the pupil’s pupils are smaller in bright light and bigger in low light.iris changes and expands involuntarily and changes the size of the pupil.
It is the pupil controlling the amount of light passing through the eye lens to the retina at the back of the eye. However, there is some inconsistency in the size and shape of the student. In younger people, the size of the pupil is usually larger, and about 20% of the population has two pupils who do not have the same size. You probably also noticed that not all students are round. Some animals, such as cats and snakes, have long pupils.
Controlling the pupil
The pupil function has two sets of muscles: Sphincter muscles narrow the pupil like a string.
The thinning muscles that radiate from the middle of the iris help to dilate the pupil.
Behind the scenes, there is a long nerve that helps the eye react to changing conditions. This nerve takes a surprising path through the body, starting with the brain, and then moving down the spinal cord, passing over the lungs, through the neck, back through the part of the brain, and finally to the student. Because of this strange way, problems with the brain, upper lungs, and some eye health problems can be discovered when there is an unexpected change in students.