Anisocoria is when your eye’s pupils are not the same size. The pupil allows light to enter the eye so that you can see.
Anyone can have pupils that differ in size with no problems. In fact, 1 out of 5 people have pupils that are normally different sizes.
Sometimes, though, having uneven pupil size can be a symptom of a serious eye problem. People who may get anisocoria include those with:
a nervous system problem
a history of damage to the eye
risk of having a stroke
a viral infection
Adie’s tonic pupil (when one pupil does not respond to light as well as the other pupil)
Anisocoria Symptoms
Often people don’t realize their pupils are different sizes. Some people only notice it when comparing old and recent photos of themselves.
However, if anisocoria develops from an eye health problem, you may notice other symptoms related to that problem. These symptoms may include:
drooping eyelid (ptosis)
problems moving your eye
eye pain
fever
headache
reduced sweating
If you experience any of these symptoms with anisocoria, call an ophthalmologist right away
Anisocoria Diagnosis
To diagnose anisocoria, your ophthalmologist will examine your pupils in both a lighted room and a dark room. This allows them to see how your pupils respond to light. This can help them figure out which pupil is abnormal.
Your ophthalmologist will also check your eyes with a slit-lamp microscope. This instrument lets your eye doctor look at your eye in small, detailed sections. That makes it easier to spot problems.
If you have other symptoms along with different pupil size, your ophthalmologist will do other tests to learn more about your condition.
Anisocoria Treatment
Usually anisocoria does not need to be treated since it does not affect eyesight or eye health.
If anisocoria is related to an eye health problem, that problem needs treatment.
If you have questions about anisocoria, be sure to ask your eye doctor. Your ophthalmologist is committed to protecting your sight.