Science Questions

When you yawn, why do your eyes water? Is it normal? John

Yes, it is. Part of the reason is that when you yawn, you squeeze you eyes tightly shut. The way that tears flow is that they come out of you lacrimal gland which is on the upper outer side of the top of your eye. They then flow in a film across your eye obliquely downwards and inwards. The tiny black dot on your lower eyelid is called a punctum, and that's where your tear duct starts. If you squeeze your eyelids tightly shut, you stop the tears flowing across your eye and into the tear duct and so they have to come out. This makes you cry a little bit, which is why tears come out when you yawn.

March 2005