We've all seen a baby take his little fist and rub it vigorously into his eye, usually accompanied by a little yawn. Rubbing his eyes is a way that the baby has of telling us he is tired—that much is pretty obvious—but why eye rubbing?
As a baby gets tired his eyes get fatigued. When he rubs his eyes (as you would rub a sore arm muscle after playing baseball), he is relieving the soreness and tension in the muscles around the eyes, in the eyes, and in the lid. As a baby becomes tired his eyes also start to become dry. Having been exposed to air for a long time, the tear film that bathes the front of the eyes in a protective layer of tears begins to evaporate. Rubbing the eyes also stimulates tearing, which helps bring moisture back into the eyes.
Tiredness aside, there are some other possible reasons why babies rub their eyes. Babies love to touch every part of their bodies to learn how their bodies will respond. When you close your eyes and rub them, you know how you can see lights and patterns on the insides of your closed lids? When a baby who isn't tired rubs his eyes, it may be because of the fascinating visual stimulation he gets from doing so; he may be experimenting with what it's like to "see" with his eyes closed.
Clearing the Eyes
Secondly, a baby may also rub his eyes if there is something irritating in them, like an eyelash. (If a baby is crying and continually rubbing his eyes, there might be something scratching his eye. Flush the eye with water and call the doctor.) Finally, maybe he's rubbing his eyes quite simply because they itch.
Adapted with permission from Why Babies Do That: Baffling Baby Behavior Explained, by Jennifer Margulis, published by Willow Creek Press. 2005 by Jennifer Margulis. All rights reserved.