Why You Wake Up With Eye Crust

What is that crust in the corner of your eyes in the morning

and why does it show up overnight? The medical term is rheum.

It is basically leftovers from the eye's cleaning system. Your eyes constantly make tears,

mucus, and oils to keep the surface smooth and trap dust.

During the day, blinking spreads tears and drains debris through the tear ducts.

While you sleep, you blink far less so that material can collect and

dry at the corners. What is in it? A mix of

dried tears, mucus, skin cells, oils, and trapped dust.