The pupil is a hole in the iris that allows light to transmit to the retina inside of the eye. Bright light causes the pupils to constrict (get smaller), and darkness causes the pupils to dilate (get larger). The pupils are constantly changing size to control the amount of light that enters the eye. This is all controlled by our autonomic nervous system automatically without us having to think about it. Pupil testing is an important part of the eye examination, and abnormal pupils can indicate eye health or overall health problems.
Some chemicals or drugs can alter pupil size, and make them less reactive to changing light conditions. Systemic drugs like morphine, codeine, or heroin can make pupils smaller. Also, exposure to some pet flea/tick products can make pupils smaller. Medications like scopolamine patches used to treat motion sickness can make pupils larger. Over the counter allergy eye drops, “get the red out” eye drops, and anti-itch creams may make the pupils larger.
Anisocoria is the condition where one pupil is a different size than the other. Some people are born with different sized pupils. Ocular surgical complications or eye injuries can cause a pupil to change size or shape. If one pupil suddenly becomes larger or smaller than the other, it is important to have an eye examination to determine the cause. Sometimes a very serious problem like concussion, cerebral aneurysm, cerebral mass, or stroke can alter the size of the pupils.
During routine eye examinations, we carefully evaluate the pupils for abnormalities. We also dilate the pupils to more carefully evaluate the health of the inside of the eye. Any sudden changes in pupil size should be evaluated to determine the cause.
Dr. James Ivanoski practices at Lakeshore Eye Care Professionals with Drs. Martha Jay and Mark German. He welcomes patients of all ages into his practice and accepts most insurance plans.
For more eye care information, visit www.LakeShoreVision.com or call 262-241-1919.