Scientists still don’t know why some people’s eyes are a certain colour. Especially rare is the change in eye colour from brown to green or from blue to brown. Usually occurring in only one eye, this condition causes a change in the colour of the iris and loss of pigment in the eye.
As pupil size changes, the pigment in the iris contracts or dilates, causing slight changes in perceived eye colour. As pupil size changes, the pigment in the iris contracts and dilates, changing the colour of the eye. Pupils can change size in response to a certain emotion, thereby changing the dispersion of the iris and the colour of the eye. Eye colour doesn’t change, but the iris may become less bright if the pupil dilates.
Changes in eye colour may not only be related to the iris, changes in other parts of the eye may cause changes in the colour of the iris. In babies, eye colour may change as more melanin is produced in the iris. Almost everyone (even blue- or green-eyed people) has brown pigment on the back of the iris. When the iris gets smaller, the brown melanin shrinks, and the eyes look darker.
Melanin and Eye Color
Conversely, blue eyes absorb less light with brown melanin, so more light bounces off the eye and appears blue. The secret to blue eyes, also known as the “sky effect,” is the low level of melanin in the iris, which scatters light, producing a brighter blue. The coloured part of the eye is called the iris, which surrounds the pupil and is filled with melanin.
Eyes with a lot of pigment in the connective tissue (called the stroma) at the front of the iris are darker, while those with less tend to be lighter. People with one colour eye closer to the pupil and the other a little further away, with a different colour on the edge of the iris are more likely to have brown eyes.
Amber eyes, often confused with brown eyes, are usually a solid gold or copper colour without the blue or green patches that are typical of brown eyes. Like gray eyes, brown eyes can “change colour” from green to light brown to gold. Since the colour itself is not exactly defined, people have wondered if brown eyes are more like chameleons that change colour depending on the environment.
But scientists don’t understand why other people have grey, brown, or multi-coloured eyes. Doctors did not find vision problems in these people, and even this “gift” is not inherited. Although this phenomenon has not yet been thoroughly studied, all scientists still agree that this is not a disease but a unique feature that only a few people have. Many people choose to have eye colour change surgery even though their natural iris functions normally.
However, since it can permanently change eye colour, it is becoming more popular with those looking for a purely cosmetic change. While there are complete, eye-catching fashion solutions out there, there’s real science behind how and why eye colour changes, leaving some people wondering if it’s possible to intentionally (and permanently) change their eye colour. Some people wear tinted contact lenses to brighten or change the colour of their eyes.
They do not completely change the colour of the eye, but (again, depending on the original colour) they can enhance it, making it more distinct. The colours in your surroundings, including lighting and clothing, can give the illusion of a change in eye colour. A change in eye colour to a yellowish or greenish tint can signify an eye ailment or disease, such as Horner’s syndrome, Fuchs’ heterochromic uveitis, or pigmentary glaucoma.
For example, your eyes may appear a darker blue if you are wearing a blue shirt. Sometimes it seems that your eyes have changed colour due to different lighting conditions that make them lighter or darker, but this is usually not the case. Some people say their eyes change colour when they experience other emotions such as happiness or sadness. This may make the eyes lighter or darker in response to an emotional situation, but it will not completely change eye colour.
Genetics and Eye Color
Sometimes a genetic mutation (change) can cause someone to have a unique eye colour. Gene mutations can also affect eye colour, resulting in different colored eyes, polychromatic eyes, and even atypical colours like purple.
Genetics determine eye colour, which usually darkens in the first few years of life. During this time, the body produces a dark pigment called melanin. A baby’s eyes may appear bluish-gray in the first few months of life, then darken as eye pigment develops. If blue-eyed children produce more melanin in the iris, their eyes may darken and turn brown or hazel.
Most babies are born with blue eyes, and everyone watches to see if those eyes change colour. But children born with brown eyes do not undergo any changes and retain this eye colour for the rest of their lives. This appears to be because more melanin develops in the iris during infancy and early childhood.
Without melanin, their irises are transparent, making the blood vessels within the eye visible. Your eyes look red because there is so little melanin in the iris, and you can see the blood vessels in the back of the eye.
This muscle can increase or decrease depending on the size of the pupil (the black middle part of the eye). It plays an important role in how the eye works by limiting the amount of light passing through the lens and retina, so it’s not just an aesthetic feature.
Some eyes also have darker or lighter coloured patches. They can “change colour” from gray to blue to green based on clothing, lighting, and mood (this can change pupil size, squeezing iris colour).
If you’re worried about a sudden change in eye color, or if you just want some colored contacts you should consider seeing an optometrist for the best solution.