Typical terms invented to fill this vacuum include sleepies, eye-snot, and bed-boogers. The correct word, however, is gound. "Collin was never one to dillydally in the morning: by the time he had rubbed the gound out of his eyes he was usually on his third Manhattan."
Source: wiktionary
Your eyes get dried mucus in them while you sleep. The stuff is sometimes called bed-boogers or eye-snot, but to be accurate, it is "gound".
Source: wiktionary
Your eyes have their own goo, too. You know that crud in the corners of your eyes when you first wake up? It's a type of rheum called gound. When you're awake, you blink away the gound.
Source: wiktionary
While you sleep, however, your rheum bundles detritus such as dust, blood cells, skin cells, and mucus into gound, the gummy yellow-y stuff sometimes known as “sleep” […]
Source: wiktionary