Eyes come in a variety of colors, from the common brown and blue to the less common green, amber, gray, and hazel. Some people even have two different colored eyes, known as heterochromia iridum. With so much natural variation in eye color, some wonder if moods can also affect eye color.
The Biology of Eye Color
Eye color is determined by the amount and type of pigment in the iris. The iris is the colored part of the eye that controls the size of the pupil to let in more or less light. The most common eye pigment is called melanin. The amount and type of melanin in the iris is what gives eyes their color.
There are two types of melanin that determine eye color:
- Eumelanin produces brown/black pigment
- Pheomelanin produces yellow/red pigment
More melanin leads to darker eye colors, while less melanin produces lighter eye colors. Here’s a breakdown of how the amount and type of melanin leads to different eye pigments:
| Eye Color | Melanin Amount | Melanin Type |
|---|---|---|
| Brown | High | Eumelanin |
| Blue | Low | Eumelanin |
| Hazel | Moderate | Eumelanin + Pheomelanin |
| Green | Low-Moderate | Pheomelanin |
| Amber | Moderate | Pheomelanin |
| Grey | Low | Eumelanin |
As you can see, the type and amount of melanin are the key factors that determine eye color. But can this pigment change in response to moods?
Do Emotions Impact Eye Color?
While some people insist that their eyes change color depending on their mood, there is no scientific evidence to support this claim. Here’s an overview of why mood cannot alter eye pigmentation:
- Melanin levels are genetically determined – The amount and type of melanin in your irises is programmed into your DNA. Melanin levels remain constant throughout life and are not influenced by emotions.
- Emotions only transiently affect the iris – Strong emotions may slightly dilate or constrict the pupil, which can make the iris appear to change color. But the pigment itself does not change.
- Color perception changes – Surrounding factors like lighting, clothing, and makeup can make eye color seem to shift. But it is just an optical illusion.
- No mechanism for melanin changes – There is no physiological mechanism by which emotions could alter the production of melanin in the eye.
In summary, it is just not biologically possible for emotions to produce any permanent or substantial change in melanin content or eye color. Any perceived color change is just an optical illusion.
Can Eye Color Ever Change?
While moods cannot change eye color, some factors can gradually alter eye pigment over a longer period of time. Here are some examples:
- Aging – Eye color can appear to change as people age as the iris becomes more cloudy, allowing less iris pigment to show through. Yellowing of the lens can also give the illusion of eye color change.
- Medications – Certain drugs like rifampin or azidothymidine can cause increased pigmentation of the iris, turning blue eyes brown. These changes may persist even after stopping the medication.
- Diseases – Some conditions like pigmentary glaucoma can increase melanin deposits in the iris.
- Injuries – Trauma to the eye can sometimes cause changes in melanin content and distribution.
However, these changes occur gradually over months or years. There is no disease or injury that could rapidly change eye color in response to shifting moods or emotions.
Can Contact Lenses Change Eye Color?
Contact lenses provide one safe and temporary way to change the appearance of your eye color:
- Tinted contacts – These lenses have a transparent tint that overlays the iris to produce a different color. While they don’t permanently alter your natural pigment, tinted contacts can enhance or brighten your natural eye color.
- Opaque contacts – These lenses completely cover the iris with colored pigment to produce a dramatic effect. Many cosplayers and Halloween enthusiasts use costume contacts to make their eyes appear a vibrant, artificial color.
Contact manufacturers offer lenses that can make your eyes look blue, green, hazel, or brighter versions of your natural shade. However, color contacts must be worn only for special occasions and not for regular, prolonged use.
Conclusion
In short, moods and emotions do not truly alter the color or pigment of the eyes. Any perceived shifts in eye color due to mood are just optical illusions. Only long-term changes like aging, medications, diseases, or injuries can gradually change melanin content and distribution in the iris. But color contact lenses provide a temporary and safe way to alter the appearance of your eye color for a special costume or event. So while your eyes may seem to change colors, it is not actually possible for emotions to produce substantial shifts in eye pigment.
