The Science Behind Hazel Eye Color

Eye color means talking about the iris of one’s eye. It is a double layered ring of muscle tissue around the pupil which controls how much light should enter one’s eyes. One of the main factors which controls eye color is the pigment called melanin. The more the concentration of melanin in the skin, the darker it is.

Talking about the eye color of the eyes, people who have brown eyes have higher concentration of melanin in both the front and back layers of the iris whereas people with hazel eyes have less melanin in the front layer of iris.

Factors That Influence the Eye Colors

There are various factors which are responsible for eye color other than melanin concentration in our eyes . Some eye problems can change eye color, such as:

Fuchs heterochromic iridocyclitis: This is when the iris gets inflamed, which can cause the eye to lose color.
Glaucoma: Glaucoma and some medicines used for treating it might change the eye’s color.
Latisse: A beauty product used to make eyelashes thicker (originally a medicine for glaucoma) can also change eye color.

Injury or Trauma

On several occasions, because of an injury or accident the eye can sometimes change its color

Genetic disorder

According to researchers at the American Academy of Ophthalmology (2017),roughly ten thousand years back, all early humans had brown eyes because they had a lot of color pigment in their eyes. But over time, changes in their genes started to reduce the amount of brown pigment in the front part of the eye, called the iris. Genetic mutations can also create more possibilities of various eye colors and it has been observed that a region on chromosome 15 plays a major role in eye color.

Eye Structure

Medications

There are various allopathic medications used to treat glaucoma, which can change your eye color permanently over time.

Heterochromia Iridum

This rare condition, found in less than 1% of people, causes someone to have two different-colored eyes. This is a complicated process, but the combination of less pigment, the texture of the iris, and light reflecting off blood vessels and tissues make the eyes look blue.

For eye colors like green, gray, or olive, these are in-between colors. They have more pigment than blue eyes but less than brown eyes. Today, there are so many different eye colors that scientists have added more categories to the color scale, beyond just blue, green, and brown.

Hazel Eye Color & Eye diseases

Hazel eyes can lead to various eye disorders including some which have been mentioned below.

Uveal Melanoma: People with hazel, green, or blue eyes are more likely to develop uveal melanoma, a rare type of cancer that affects the middle layer of the eye.

Skin Cancer: Individuals with hazel eyes have a higher chance of getting basal cell carcinoma and squamous cell carcinoma, two common types of skin cancer.

Age-Related Macular Degeneration: Those with light-colored eyes, including hazel, are at a greater risk of developing age-related macular degeneration, which can affect vision as they get older.

Corneal Opacity and Cataracts: People with lighter eye colors are more likely to develop conditions like corneal opacity and cataracts, which can cloud the eye and impair vision.

Refractive Errors: Those with lighter eyes are at an increased risk of experiencing refractive errors, such as nearsightedness or farsightedness.

How does light impact various eye colors?

It’s true that eyes change color in different natural conditions depending upon how particular light and sunlight gets hit in the eyes and ultimately spreads in the iris. Melanin in the iris absorbs sunlight of different wavelengths. When the concentration of the melanin is less it gets reflected off the iris whereas when more in concentration the eyes absorbs more light and reflects less from the iris.

Hazel eyes, typically a blend of brown, green, and gold, can sometimes display shades of blue as well and such eyes are often termed as blue hazel eyes. One of the distinctive features of hazel eyes is the way they can appear to have different colors in various parts of the iris. Often, there is a noticeable difference in hue around the pupil compared to the outer rim, creating a unique “sunburst” effect that adds depth and dimension to the eye color. This variability in tone can make hazel eyes appear to shift in color under different lighting conditions.