11/18/2025
Sleep crust, also known as eye gunk or by its technical term, rheum, is a common occurrence. Rheum is a harmless mixture of exfoliated skin cells, oils, and tears produced or shed that accumulate in the eyes. We all get that crusty stuff in the corners of our eyes when we wake up in the morning. It is all part of a good night's sleep.
This buildup happens because, during sleep, you do not blink, allowing secretions and debris to collect and dry in the corners of your eyes and along the eyelash line.
This residue is a result of the eye’s normal protective processes. Blinking throughout the day helps flush away mucus and other debris from the surface of the eye.
Therefore, finding crusty residue in the corners and along the lash line of your eyes is normal, unless it is accompanied by symptoms such as redness, pain, or excessive discharge, which may indicate an underlying condition. It should be white or light cream color—which is normal.
If the discharge is yellow or green, that can be a sign of bacterial conjunctivitis—a common form of pink eye. There are also chronic conditions, like blepharitis (a type of inflammation), dry eye, and allergic conjunctivitis that can cause sleep crust. In some cases, it could be enough to make your eyes stick together. In those cases, see an eye care professional.
Sources:
www.healthcare.utah.edu
www.healthline.com
www.aao.org
Photo sources:
www.reichpharm.com
www.healthcare.utah.edu
www.amconlabs.com
