ELI5: What exactly is the “sand” that forms around your eyes after you wake up and how it is formed, biologically speaking?

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When you blink, your eyelids push out dried tears, mucus, oils, dirt, and dead cells. When you sleep, you don’t blink, so these substances build up in the corners of your eye and form a crust.


Dried tears form a clot of salt and mucosal proteins. It serves an evolutionary purpose of sealing your eye against moisture loss while you sleep. Without it, your eyes might dehydrate enough to damage your vision or permit an infection to set in and fester. I am not an eye doctor, please correct me if necessary.


Is there an efficient way to remove it? I manually take them out everyday from the inside of my eyeballs sometimes, which is often a a white slimy thing that extends all the way into the insides


It changes depending on things. But ultimately it’s a filter pushing out debri. Dirt from the day can be in it. Puss if you have an infection. *pus


when you sleep your eyes build up dead skin cells and other extremities in the sides of your eyes so they can stay clean and they can also push other dead skin cells that’s near them. so technically your eyes and eyelids are a window washer and at night it’s just a car wash.