In last month’s blog post on how a concussion affects vision, we discussed that having one pupil larger than the other is a cause for concern if you’ve recently suffered a concussion. This month, we’re going to take a deeper dive into that condition, known as Anisocoria.

Causes

Anisocoria naturally affects about one-fifth of the population without any problems in vision. Outside of being born with the condition, most people who are affected by it usually have had an eye disorder of some sort or an issue with their nervous system.

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Photo from The Express UK Article on David Bowie

According to the Merk Manual, eye disorders include birth defects, injuries to the eye, drugs, inflammation of the pupil itself, or are glaucoma-related. The late David Bowie, a well-known British musician and icon, is an excellent example of anisocoria. Most people think he had different colored eyes, a condition known as heterochromia, but he did, in fact, have anisocoria as a result of being hit in the eye as a teenager. To learn more about that story, here’s the link to The Express UK article on David Bowie.

Sometimes there are issues with the nervous system that result in one pupil being larger than the other. Those issues include pressure on the 3rd cranial nerve (nerve affecting the movement of the eye), stroke, injury, tumors, infections, or problems with the autonomic nervous system that result in drooping eyelids and misaligned eyes.

Symptoms to Watch For

See a medical professional if you experience any of the following and your pupils suddenly appear to be different sizes:

    • Drooping eyelid 
    • Double vision
    • Loss of vision
    • Headache or neck pain
    • Eye pain with bright light
    • Recent injury to the head or eye

 

Treatment

Eye-care professionals will first take a look at your history — and even perhaps an old photograph or your driver’s license — to see if anisocoria has been present all along. Then they will perform a series of examinations to make sure that both of your eyes are tracking correctly, responding to light and dark appropriately, and will use a slit lamp to magnify your eye for further examination.

While there isn’t anything that can be done to treat the condition itself, there may be a need and/or opportunities to treat the underlying condition that is resulting in anisocoria.

For more information on this condition, check out All About Vision, the Merk Manual for Professionals, and the American Academy of Ophthalmology.