Chemosis is swelling of the tissue that lines the eyelids and surface of the eye (conjunctiva).
Fluid-filled conjunctiva; Swollen eye or conjunctiva
Chemosis is a sign of eye irritation. The outer surface of the eye (conjunctiva) may look like a big blister. It can also look like it has fluid in it. When severe, the tissue swells so much that you can't close your eyes properly.
Chemosis is often related to allergies or an eye infection. Chemosis can also be a complication of eye surgery, or it may occur from rubbing the eye too much.
Rubenstein JB, Tannan A. Allergic conjunctivitis. In: Yanoff M, Duker JS, eds. Ophthalmology. 4rd ed. St. Louis, MO: Elsevier Mosby; 2014:chap 4.7.
Franklin W. Lusby, MD, ophthalmologist, Lusby Vision Institute, La Jolla, CA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.