Blue eyes are a unique and striking eye color that many people find attractive. However, some wonder if blue eyes are a permanent eye color or if they can change over time. The main factors that determine eye color are genetics and melanin levels, and these typically remain constant throughout life. However, there are some circumstances in which blue eyes may appear to change color slightly, or even disappear entirely over time.
What makes eyes blue?
Human eye color is determined by the amount and type of melanin pigments in the iris. Brown eyes contain large amounts of melanin, while blue eyes contain low levels of melanin. The iris contains very little melanin in blue eyes, which allows more light to be reflected and scattered. This scattering effect results in the blue appearance.
The main gene responsible for blue eyes is called OCA2. This gene regulates melanin production. The OCA2 gene contains a specific variation unique to people with blue eyes. This variation limits the amount of melanin produced in the iris, resulting in less pigmentation and blue color.
People must inherit the OCA2 variation from both parents to have blue eyes. Since eye color is a polygenic trait, other genetic factors also influence the exact shade of blue. But in general, the OCA2 gene mutation is the main reason eyes appear blue instead of brown.
Do blue eyes change over time?
For the most part, the genetic and melanin factors that make eyes blue remain constant over a person’s lifetime. This means that blue eyes do not really change color or turn brown over time. However, some factors can make blue eyes appear slightly different as a person ages.
Decrease in collagen
One factor that may make blue eyes look different is decreasing collagen levels. Collagen provides structure to the tissues in the iris and other eye structures. Over time, collagen breaks down naturally. Loss of collagen can change the shape and formation of the iris very slightly. This can lead to subtle changes in how light scatters and reflects from blue irises.
Increased melanin
While unusual, some research indicates that melanin production may increase slightly over time in blue eyes. More melanin means less light scattering and a darker eye color. However, this change is typically very minimal and not enough to make blue eyes turn brown. The mechanism behind this melanin increase is not fully understood.
Yellowing of the eyes
As people age, the lenses in the eyes gradually yellow. This is due to protein changes and oxidative damage over time. A slight yellowish discoloration from the lenses can make blue eyes appear less bright and vivid. This can create a darker or muddier looking blue. But the actual melanin pigment in the irises remains the same.
Can blue eyes turn brown?
It is extremely rare for blue eyes to turn brown over a person’s lifetime. There are a few circumstances in which this may occur:
Diseases affecting melanin
Certain medical conditions can impact melanin production, like pigmentary glaucoma or melanoma. If these diseases increase melanin in the iris enough, blue eyes could potentially turn brown or hazel. But this is very uncommon.
Injuries causing melanin overproduction
Trauma to the eye area, like a punch or a foreign object entering the eye, could potentially trigger changes in melanin production as the eye heals. This melanin overproduction could lead to a color change. However, there are very few real-life cases of this happening.
Medications
Certain medications used to treat eye issues like glaucoma have been associated with increased iris pigmentation in rare instances. Latanoprost and bimatoprost eye drops may be able to cause blue eyes to turn brown in some cases, but side effects are very rare.
Harmless iris freckles
Some people with blue eyes develop benign freckles on their irises as they age. These freckles are clusters of pigment cells called melanocytes. The freckles appear brown and may make blue eyes look hazel or brown. But the natural color remains blue under the freckles.
Can blue eyes disappear?
While blue eyes turning brown is very unlikely, some health conditions can make blue eyes appear to disappear entirely:
Cataracts
A cataract causes the lens of the eye to turn cloudy. Over time, cataracts make the iris and all eye colors appear darker and can cause loss of color intensity. Some people report blue eyes looking darker after cataract surgery as well. Advanced cases of cataracts can make distinguishing iris colors difficult.
Vitreous opacities
The vitreous is the jelly-like substance inside the eye. Clumps or opacities in the vitreous can block light as it passes through to the retina. This can make blue eyes seem much darker.
Corneal scarring
A scarred or damaged cornea will refract light differently. This disruption in light passage can take away the bright blue appearance of blue eyes. Corneal scarring is common after injuries, infections, and ulcers.
Conclusions
In summary, blue eyes remain blue for life in the vast majority of cases. Subtle changes related to aging and medical conditions can sometimes make blue eyes look slightly different over time. But it is very rare for blue eyes to turn brown completely or become indistinguishable from other colors. The unique genetics behind blue eyes stay constant over a lifetime. With proper eye care and health, dazzling blue eyes can remain vibrant for years.
References
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