How Your Iris and Your Pupil Impact Your Vision
The iris is the colored part of the eye and the pupil is a hole in the center of the iris. The iris controls the amount of light that passes through the pupil into the eye. In dim light, the iris contracts, dilating the pupil so that more light can get in. When it is bright, the iris constricts the pupil to minimize the amount of light passing through to the retina. Lighting is not the only factor that can cause the pupils to dilate or constrict. Strong emotions, certain drugs, injuries and medical conditions can affect pupil size.
Iris Color and Genetics
The iris is the main point of interest when we look at faces, but you may not know how much information is contained in it.
The color of your iris is controlled by your genes. It is not as simple as inheriting a parent’s eye color. We still do not know how many genes are involved. The color is created by the pigment melanin. People with no pigment have light blue eyes. The most common eye color is brown. While there are many superstitions and silly ideas about the meaning of your eye color, it can give you some real clues to health conditions for which you may have a predisposition.
As we learn more about the genes tied to eye color, we learn more about what eye color reveals about your genetic makeup. The most well-known example is the myth that all-white cats with blue eyes are always deaf. In reality, about 65% to 85% of these cats are hearing-impaired because the gene that causes the all-white coat can also cause blue eyes and can also cause congenital deafness. We do not yet know why it is more likely to cause deafness when it causes blue eyes.
Iris to Replace Fingerprints
Your irises are even more unique than your fingerprints. In the near future, iris scans may replace fingerprints as a means of identification. It is believed that the iris scan will be more reliable because there are more points to verify in the iris than a fingerprint, and fingerprints can get worn down over time from manual labor or working with chemicals.
If you have ever been pulled over and had the unpleasant experience of having a flashlight in the eyes, you may have thought it was just unnecessary rudeness. It is actually a tactic police use to quickly assess whether a person may be intoxicated. Likewise, EMTs will check pupil reaction in their initial assessment of patients. Pupil reaction can tell a trained medical professional a lot about your condition. They will check the reaction of each pupil, and do a swinging test to see if both pupils react the same. Pupil testing is also an important part of a comprehensive neurological exam.
To learn more about your eyes and what they may be trying to tell you about your overall health, talk to an experienced ophthalmologist. Search this directory for a list of ophthalmologists near you.