Mucus produced by the eyes during sleep.
{{quote-text|en|year=2002|author=Peter Novobatzky; Ammon Shea|title=Depraved and Insulting English
{{quote-text|en|year=2004|author=Bart King; Chris Sabatino|title=The Big Book of Boy Stuff
(quote-text)
Gummy matter in sore eyes.