Rheum - wikipedia Rheum This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( April 2018 ) For the genus, see Rheum ( plant ). Rheum in a cat 's eyes Rheum ( / ˈruːm / ; from Greek : ῥεῦμα rheuma `` a flowing, rheum '' ), also known as gound, is thin mucus naturally discharged from the eyes, nose, or mouth during sleep ( cf. mucopurulent discharge ). Rheum dries and gathers as a crust in the corners of the eyes or the mouth, on the eyelids, or under the nose. It is formed by a combination of mucus ( in the case of the eyes, consisting of mucin discharged from the cornea or the conjunctiva ), nasal mucus, blood cells, skin cells, or dust. Rheum from the eyes is particularly common. Dried rheum is commonly called sleep, sleepy - seeds, sleepy buds, sleepy sand, eye goop, cheese, or sleepy dust. When the individual is awake, blinking of the eyelid causes rheum to be washed away with tears via the nasolacrimal duct. The absence of this action during sleep, however, results in a small amount of dry rheum accumulating in corners of the eye, most notably in children. A number of conditions can increase the production of rheum in the eye. In the case of allergic conjunctivitis, the buildup of rheum can be considerable, many times preventing the sufferer from opening the eye upon waking without prior cleansing of the eye area. The presence of pus in an instance of heavy rheum buildup can indicate dry eye or conjunctivitis, among other infections. In infants, the tear ducts ( that drain the tears ) occasionally fail to open, resulting in the overflow of tears onto the cheeks ( epiphora ) and rheum deposition on the surrounding skin. See also Mucopurulent discharge References Jump up ^ `` Rheum ( discharge ) ''. Memidex Dictionary / Thesaurus. 2009. Retrieved 2009 - 04 - 22. Jump up ^ Amodio, Aimee. `` Where Do Eye Boogers Come From ? '', Families.com blog ^ Jump up to : Hiskey, Daven. `` What the ' Sleep ' In Your Eyes Is '', Today I Found Out, 23 February 2011. Jump up ^ Shorter Oxford English Dictionary. Oxford University Press. 2007. ISBN 978 - 0 - 19 - 920687 - 2. ^ Jump up to : Eric Partridge, Paul Beale, ed., A Dictionary of Slang and Unconventional English, 8th edition, 1984, s.v. Jump up ^ http://www.nbcnews.com/health/body-odd/are-yours-crusty-or-wet-truth-behind-eye-boogers-ew-f1C6437167 External links Look up rheum in Wiktionary, the free dictionary. Eye Discharge Retrieved from `` https://en.wikipedia.org/w/index.php?title=Rheum&oldid=845057868 '' Categories : Symptoms Ophthalmology Body fluids Hidden categories : Articles needing additional references from April 2018 All articles needing additional references All articles with unsourced statements Articles with unsourced statements from April 2018 Talk About Wikipedia Български Català Čeština Deutsch Español Euskara فارسی Français Galego 한국어 Íslenska עברית Lëtzebuergesch Nederlands 日本 語 Norsk Português Русский Tagalog தமிழ் Tiếng Việt 粵語 中文 14 more Edit links This page was last edited on 9 June 2018, at 01 : 45 ( UTC ). About Wikipedia

Question: where does the crust in your eyes come from
Answer: mucin discharged from the cornea or the conjunctiva