As you sleep, a silent visitor flits above: a sleep fairy. She reaches into a magic pouch, smaller than a thimble, and retrieves magic dust. Hours later you awaken, rested, but a rub of your eyes reveals sand around your lashes. The truth behind "eye sand," also known as eye boogers, sleep dust, eye gunk and eye schnooters, is not quite as delightful as the fictional ministrations of a sleep fairy. Eye boogers are a substance that forms on the outer corners of the eye or along the lash line, usually during sleep. They can be dry, with a sand-like consistency, or can feel wet, like mucus.
To understand eye boogers, we must first learn more about tears, the liquids secreted around the eyes. Tears are made of three layers: a lipid layer, an aqueous layer and a mucin layer. The lipid, or oily layer, is called meibum and is made by the meibomian glands at the rim of the eyelid. The aqueous layer comprises water, electrolytes and proteins. Mucin, a type of protein, is secreted by the conjunctiva, a thin, clear membrane that covers the white portion of the eye. During the day, tears keep the eyes moist, wash away foreign particles and clear the eyes of discharge [source: Managed Care Eye Institute].
At night, when blinking all but ceases, this discharge — a combination of mucus, oil, dust and skin cells — begins to pool in the corners of the eyes and along the lashes. Rheum, thin mucus that acts as a natural defense mechanism for eyes, also collects in the corners of the eyes and around the lashes at night. Rheum is made of mucin and meibum. This combination of discharge and rheum is called gound, and it is gound that overnight transforms into eye boogers [source: Surtenich].
So, why are some eye boogers dry while others are wet? It's all in the eye of the beholder. People who have allergies or frequently rub their eyes may have eye boogers that are wet. Those whose eyes are typically dry are more likely to have dry, sandy eye boogers. Contact wearers can experience a range of eye booger consistencies, from dry to wet, depending on how their eyes respond to the artificial lenses.
If you wake up with eyes plastered by boogers, use a warm, wet washcloth to soften and then remove them. They're not dangerous, just a bit inconvenient [source: Nierenberg].