Rheum

Sleep sand ( also sleep grains, sleeping in the eyes or Matzel ) is the colloquial name for the accumulation of dried secretions from the glands of the eyelid (eye or eyes butter mucus ) arising during sleep and then collect at the lid margin.

Formation

The anterior portion of the eye must be kept wet. This is done by tear fluid and phlegm from the so-called goblet cells of the conjunctiva. Due to the oily liquid meibomian glands of the eyelid, which mixes with the tear fluid, reduces the evaporation of the moisture film.

During sleep, the fluid production is reduced in the eye and remains of the greasy secretion of the meibomian glands may accumulate on the inner canthus of the eye and become encrusted with time. Because of their color similarity with sand they are referred to as " sleeping sand " in the vernacular. There are also more regional vernacular names.

The sleeping sand consists in addition salts and proteins from cell debris by white blood cells that die in defense against bacteria (mostly harmless ).

After the eye opening the foreign body sensation in the eye led to the rubbing of the eye and removal of the sand bed. Man " rubs the sleep from his eyes. " A possible distribution of the secretion on the cornea of ​​the eye leads to an obscuring the view to the secretion, for example, eliminated by blinks.

If there is inflammation of the conjunctiva (conjunctivitis) and the lid margin ( blepharitis ), a pathological increase of mucus occur.

The sleeping sand is partially, eg in children's fairy tales, associated with the legendary figure Sandmann.