Eye discharge, or “sleep” in your eyes, is a combination of mucus, oil, skin cells and other debris that accumulates in the corner of your eye while you sleep. It can be wet and sticky or dry and crusty, depending on how much of the liquid in the discharge has evaporated.
Other slang terms used to describe eye discharge include eye boogers, eye mattering, eye gunk and eye pus.
Sometimes called rheum, eye discharge has a protective function, removing waste products and potentially harmful debris from the tear film and the front surface of your eyes.
Your eyes produce mucus throughout the day, but a continuous thin film of tears bathes your eyes when you blink, flushing out the rheum before it hardens in your eyes.
When you’re asleep — and not blinking — eye discharge collects and crusts in the corners of your eyes and sometimes along the lash line, hence the term “sleep in your eyes.”
Some sleep in your eyes upon waking is normal, but excessive eye discharge, especially if it’s green or yellow in color and accompanied by blurry vision, light sensitivity or eye pain, can indicate a serious eye infection or eye disease and should be promptly examined by your eye doctor. If you haven’t established an eye doctor
Where Does Eye Mucus Come From?
Eye discharge is a function of your tear film and a necessary component of good eye health. Eye rheum primarily consists of thin, watery mucus produced by the conjunctiva (called mucin), and meibum — an oily substance secreted by the meibomian glands which helps keep your eyes lubricated between blinks.
When not washed away by tears, the accumulated debris, or “mattering,” collects in the inner corner of the eye as well as along the lash line.
Sleep in your eyes usually isn’t cause for alarm, but if you notice a difference in consistency, color and quantity of eye gunk, it could indicate an eye infection or disease.
Common eye conditions associated with abnormal eye discharge include:
Conjunctivitis. Eye discharge is a common symptom of conjunctivitis (pink eye), an inflammation of the conjunctiva — the thin membrane that lines the “white” of the eye (sclera) and the inner surface of the eyelids.
In addition to itchy, gritty, irritated and red eyes, conjunctivitis typically is accompanied by white, yellow or green eye mucus which can form a crust along the lash line while you sleep.
In some cases, eyelid crusting can be so severe that it temporarily seals your eye shut.