Subconjunctival Hemorrhage (Bloody Eye)
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What is a subconjunctival hemorrhage?
A subconjunctival hemorrhage is a bright red spot on the white of your eye (sclera). It's caused by a popped blood vessel under the thin, clear tissue (conjunctiva) that covers the sclera. A subconjunctival hemorrhage can cause a small red spot on your eye or it can cover the entire sclera, causing a dramatic red, bloody eye.
Though it may look scary, a subconjunctival hemorrhage is harmless and typically goes away without treatment within a week or two.
A subconjunctival hemorrhage is blood on the front of the eye. Don't confuse it with blood in the front of the eye. Blood in the eye (behind the clear cornea) is a serious condition called a hyphema. Unlike a subconjunctival hemorrhage, a hyphema requires immediate attention from an eye doctor.
Subconjunctival hemorrhage symptoms
Subconjunctival hemorrhages usually don't have any symptoms.
(The medical terms symptom and sign are often confused or misused. Symptoms are indicators of a condition that can be recognized only by the persing experiencing them. Blurry vision is an example of a symptom. Signs are indicators that can be seen by others as well as the person experiencing them. A red eye is an example of a sign.)
A subconjunctival hemorrhage doesn't cause symptoms like blurry vision or eye pain. The only symptom a bloody eye from a popped blood vessel might cause is a mild scratchy feeling on the surface of your eye.
But the primary sign of a subconjunctival hemorrhage — a bright red spot on the white of your eye — is unmistakeable. It can be a relatively small spot or cover a large area of your sclera. Also, it might start as a small spot and get larger as the day goes on.
Sometimes, the bloody spot from a subconjunctival hemorrhage can expand to cover the entire white of your eye.
In most cases, a subconjunctival hemorrage will disappear on its own within a week or two. During this time, the spot will become less red and more yellow in color as the blood is resorbed (removed) by the body. If a subconjunctival doesn't go away completely or get significantly smaller within two weeks, see an eye doctor.
What causes a subconjunctival hemorrhage?
Something as simple as a cough or a sneeze can cause a subconjunctival hemorrhage and bloody eye.
Other potential causes include:
A sudden increase in blood pressure (e.g., from lifting something heavy)
Straining due to constipation
Drug side effects
Risk factors for subconjunctival hemorrages include:
High blood pressure
Having a "cold" or allergies (that increase coughing and sneezing)
Wearing contact lenses (increases eye rubbing)
Use of aspirin or blood thinners
Aging (over age 50)
Blood clotting disorders
Vitamin K deficiency
But often, the cause of a subconjunctival hemorrhage is unknown.
How are subconjunctival hemorrhages treated?
There really is no treatment for subconjunctival hemorrhages. In some cases, eye drops (artificial tears) are recommended to keep the surface of the eye well-lubricated while the natural healing process takes place.
If you are taking aspirin, blood thinners, or other medications, continue taking them unless your doctor instructs you to do otherwise.
How to prevent subconjunctival hemorrhages
Follow these tips to avoid a bloody eye from a popped blood vessel under the conjunctiva:
Avoid rubbing your eyes. If your eyes itch, see an eye doctor to determine the cause and possible treatments.
Wear contact lenses responsibly. Clean and disinfect your contacts as directed, and don't overwear your lenses.
Stay healthy. Get plenty of exercise and rest and eat a healthful diet to avoid getting sick.
Control your allergies. See your physician or eye doctor to help prevent eye allergies and allergy-related coughing and sneezing.
Keep any blood disorders or health problems (e.g., diabetes; hypertension) under control with routine health care visits.
Remember: Subconjunctival hemorrhages are harmless and usually go away within a week or two. But if you have a persistent bloody eye or frequent popped blood vessels on your eye, see an eye doctor.
Subconjunctival hemorrhage (broken blood vessel in eye). Mayo Clinic. August 2019.
Subconjunctival hemorrhage. Cleveland Clinic. February 2018.
Subconjunctival hemorrhage: Risk factors and potential indicators. Clinical Ophthalmology. June 2013.
Page published in March 2019
Page updated in September 2021