Ever wondered why we wake up with gunk in the corner of our eyes?
Pretty much every morning, we find ourselves wiping away the sleep dust from our peepers, but we’ve never really known why. Until now.
Sleep gunk is caused by tears, or rather the teary film that coats our eyes. Part of this film is made up of mucus and a water-based tear solution, but another part consists of an oily substance called meibum, which is made up of fatty acids and cholesterol.
Meibum not only keeps our eyes moist, but also helps prevents our tears from constantly streaming out of our eyes. Handy.
At normal temperature, this is a clear, oily fluid. But the minute the temperature drops one degree, it turns into a white, waxy solid. Ooh.
When we sleep, the body cools down a bit, so this helps to explain why the meibum goes waxy and collects in the corners of our eyes.
Sleep also ‘relaxes the [muscular] action on the [meibomian] gland ducts… [which] is sufficient to cause far in excess of the normal to exude onto the lids and eyelash roots during sleep’, Australian ophthalmologist Robert G. Linton tells the BBC.
Basically, we produce more meibum at night, leading to more eye gunk.
So now you know.