Free interactive tool
Uneven pupils, explained.
A difference in pupil size is called anisocoria. Choose a scenario and change the lighting conditions to see how each one appears to the examining doctor, and how the pupil, the eyelid, and the response to light and to a near target point to the cause. Then use the short self-check below.
The eyes are
Scenario
A short self-check
This does not diagnose anything. It helps you judge whether a pupil difference is likely harmless or worth having looked at.
Important: This tool is for educational purposes only. It cannot diagnose anisocoria or any other condition and does not replace an eye examination. A pupil difference that is new, changing, or comes with a drooping eyelid, double vision, eye pain, a severe headache, or a red eye should be assessed promptly, and some combinations are emergencies. This tool does not store or transmit any data you enter.