Why are my eyes changing color?

People have always been fascinated about eye color and is the main reason why many buy cosmetic colored contact lenses to change their appearance. There are a number of reasons why eye color can change on its own. Before discussing what can change eye color, one needs to understand what gives our eyes their natural color. 

The iris is the muscle part of the eye which expands and contracts to control the size of the pupil, the black circle in the center. The pupil gets smaller in bright light situations and larger in low light. The iris can also contract when focusing up close, like when you are reading. When the pupil changes size, the colored pigments in the iris compress or spread apart and this can slightly change the perceived eye color.

During the first months of life, an infant’s eye may look blue or bluish gray, but then darkens over time. This is because eye color is determined by your genes and the melanin level in your body. As the baby ages, the melanin level increases around the pupil, making the eye darker. 

There are many factors that can cause eyes to change colors—or appear to have different colors—including various diseases, medications and trauma,

Some diseases that can cause eye color changes include:

– Horner’s Syndrome: This is a rare condition that is usually the result of a stroke, tumor, trauma or spinal cord injury damaging nerves. This can result in a lighter color to the iris, drooping eyelid, uneven pupil size and the inability to sweat on that side of the face.  

– Pigment dispersion syndrome/ pigmentary glaucoma: In these conditions. the pigment on the back of the iris is disrupted and comes off the iris, causing a lighter eye color due to less melanin pigment. 

-Fuchs heterochromic iridocyclitis: This is an inflammation of the iris whose cause is unknown, but results in atrophy of the iris, a loss of pigment in the iris and a lighter eye color. These patients will often have one brown eye and one blue eye as seen in the photograph above. Cataracts and glaucoma can also occur and lead to vision loss if not treated.

-Wilson’s disease: This is a very rare condition related to elevated copper in the body from liver disease and this condition requires immediate medical attention. This disease results in a greenish/orange ring in the cornea, which is the clear part of the eye that is in front of the iris. 

There is another cause of eye color changes due to the cornea and not the iris called “arcus senilis.” A hazy blue or white ring on the cornea develops from a build-up of a natural fatty substance called lipids.  Most older patients have some degree of arcus senilis and this is harmless. If these color changes in the cornea occur in a younger person, then that can be a sign of elevated blood cholesterol and/or triglycerides and needs to be evaluated by the patient’s medical doctor.

Eye color can also change from medication. One class of glaucoma medications called “prostaglandins” can cause permanent eye color changes. This usually makes the eyes a darker shade of their natural color over time. These eye drops should be evaluated carefully before starting them in patients with naturally colored green, hazel or blue eyes.  

If you notice any new color change in either of your eyes, see your eye doctor right away. Eye color is one of the many things a doctor will look at in assessing general eye health. If there are problems, early treatment can make a big difference.