Discharge is what people refer to as “sleep” in your eyes. Because you’re not blinking, the mucus or discharge in your eyes hardens. A common misconception about sleep sacks is that they cause a crust to form in the corners of your eyes as you sleep. Goopy eyes and eye boogers are other names for the same thing.
Muck, oil, skin cells, and other particles collect in the corners of the eyes as you sleep, resulting in ocular discharge. This oily material is released by the conjunctiva and the meibomian glands, which create it. Between blinks, this material helps to keep your eyes moist. The discharge can be either moist and sticky or dry and crusty, depending on the amount of liquid it contains.