Is it normal for pupils to be light brown?

The human eye is divided into the cornea and the pupil. The pupil is very important for the eye. Through the pupil, we can see things in the outside world and transmit them to the brain. It is the most important part of our body. The color of the pupil is also different. This is generally closely related to the body's genetic factors. It is normal for the pupil to be light brown. It is related to personal genes.

Is light brown pupil color normal?

It is normal for pupil color to be light brown, which is related to genetic factors.

The most common iris color in Asians is dark brown, but some people have lighter brown.

In fact, the pupil is colorless. The color is in the iris: The iris, also known as "iris", is located between the cornea and lens of the eye. There is a circular hole with a diameter of 2.5 to 4 mm in the middle. This is the pupil we are familiar with.

The iris contains pigment, and its color varies from race to race. What people usually call "eye color" is actually the color of the iris. The irises of different races are different. The yellow race has more pigment, which is brown in color and looks black from a distance, while the white race has less pigment, which is light gray or light blue in color.

There are uneven wrinkles on the surface of the iris. Studies have shown that these wrinkles are different for everyone, just like fingerprints, and they do not change. Based on this characteristic of the iris, an electronic password door lock is made. When the door opener puts his eyes close to the scanning hole, the scanning device will scan the image of the iris and compare it with the pre-set pattern. If they match, the door lock will open automatically.

There are muscles in the iris tissue that regulate pupil size, namely the sphincter pupillae and the dilator pupillae, which are controlled by the parasympathetic oculomotor nerve and the sympathetic nerve respectively. The coordination of the two maintains the relative stability of pupil size. By changing the size of the pupil diameter, the brightness of light reaching the retina can be maintained at an appropriate and stable level.

Research has found that the iris of our human eye is made up of five layers of tissue. They are the endothelial cell layer, anterior limiting membrane, stromal layer, posterior limiting membrane, and posterior epithelial layer. Among these five layers of tissue, the matrix layer, anterior limiting membrane and posterior epithelial layer contain many pigment cells. The amount of pigment contained in these cells determines the color of the iris.

The more pigment the pigment cells contain, the darker the color of the iris and the darker the color of the eyeball; the less pigment the less the color of the iris and the lighter the color of the eyeball.

The pigment content in pigment cells is consistent with skin color and is related to racial genetics. Orientals are colored people, with more pigment in their irises, so their eyes appear black; Westerners are white people, with less pigment in their irises and blood vessels distributed in the matrix layer.