Crossing your eyes

How it works

Each eye has a muscle on its inner side, the medial rectus, that pulls it toward the nose². When you look at something close, both muscles pull at once. The eyes turn inward so that each one points at the same object. This is called convergence¹.

Convergence is a reflex. It runs whenever you look at something near, along with two other changes. The lens thickens to focus, and the pupils shrink¹. Crossing your eyes on purpose means pushing this reflex to its limit. You aim both eyes at a point just in front of your nose, or at your nose itself. Then you hold them there with no target.

Nearly everyone with normal two-eyed vision can do it. People with strabismus, where one eye already points a different way, may find it hard or impossible³.

A common warning says your eyes will stick if you cross them too long. There is no evidence for this. Strabismus is caused by muscle imbalance, nerve problems, or unequal vision in the two eyes, not by crossing them on purpose³. Holding the cross for a long time can give you a headache or brief double vision. Both go away when you relax.

Try it

1. Hold a finger up at arm’s length and look at it.
2. Bring the finger slowly toward your nose. Keep it in focus as one finger, not two.
3. When the finger touches your nose, your eyes are fully crossed.
4. Take the finger away and try to keep your eyes where they are.
5. Look at something far away to release the cross.