Eye redness is most often due to swollen or dilated blood vessels. This makes the surface of the eye look red or bloodshot.
Bloodshot eyes; Red eyes; Scleral injection; Conjunctival injection
There are many causes of a red eye or eyes. Some are medical emergencies. Others are a cause for concern, but not an emergency. Many are nothing to worry about.
Eye redness is often less of a concern than eye pain or vision problems.
Bloodshot eyes appear red because the vessels at the surface of the white portion of the eye (sclera) become swollen. Vessels may swell due to:
Eye infections or inflammation can cause redness as well as possible itching, discharge, pain, or vision problems. These may be due to:
Other potential causes of eye redness include:
Sometimes, a bright red spot, called a subconjunctival hemorrhage, will appear on the white of the eye. This often happens after straining or coughing, which causes a broken blood vessel on the surface of the eye. Most often, there is no pain and your vision is normal. It is almost never a serious problem. It may be more common in people who are taking aspirin or blood thinners. Because the blood leaks into the conjunctiva, which is clear, you cannot wipe or rinse the blood away. Like a bruise, the red spot will go away within a week or two.
Try to rest your eyes if redness is due to fatigue or eye strain. No other treatment is needed.
If you have eye pain or a vision problem, call your eye doctor right away.
Go to the hospital or call your local emergency number (such as 911) if:
Call your health care provider if:
Your provider will perform a physical exam, including an eye exam, and ask questions about your medical history. Questions may include:
Your provider may need to wash your eyes with a saline solution and remove any foreign bodies in the eyes. You may be given eye drops to use at home.
Dupre AA, Wightman JM. Red and painful eye. In: Walls RM, Hockberger RS, Gausche-Hill M, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed. Philadelphia, PA: Elsevier; 2018:chap 19.
Gilani CJ, Yang A, Yonkers M, Boysen-Osborn M. Differentiating urgent and emergent causes of acute red eye for the emergency physician. West J Emerg Med. 2017;18(3):509-517. PMID: 28435504 pubmed.ncbi.nlm.nih.gov/28435504/.
Rubenstein JB, Spektor T. Conjunctivitis: infectious and noninfectious. In: Yanoff M, Duker JS, eds. Ophthalmology. 5th ed. Philadelphia, PA: Elsevier; 2019:chap 4.6.
Reviewed By: Franklin W. Lusby, MD, ophthalmologist, Lusby Vision Institute, La Jolla, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.