A subconjunctival hemorrhage is leakage of blood from tiny blood vessels located underneath the thin, clear membrane (conjunctiva) that lies atop the white of the eye (sclera).
The pooling of this blood under the conjunctiva causes the affected area of the sclera to turn bright red. This red area can be quite small, or it can cover the entire white of the eye.
Though subconjunctival hemorrhages look scary, they typically do not cause any vision problems and they resolve without treatment within a week or two.
But any time you develop a red eye, you should see an eye doctor to determine if the redness is due to a harmless subconjunctival hemorrhage or a more serious condition, such as an eye infection.
What causes a subconjunctival hemorrhage?
Although it’s not always possible to identify the exact cause of a subconjunctival hemorrhage, possible factors include:
Use of aspirin or blood thinners
Trauma to the eye
Eye surgery, including LASIK and cataract surgery
A blood clotting disorder
How are subconjunctival hemorrhages treated?
Lubricant artificial tears can soothe an eye that has a subconjunctival hemorrhage, but eye drops cannot repair the broken blood vessels.
If you are taking aspirin or blood thinners, continue using them unless your doctor specifically instructs you to do otherwise.
Do not rub your eye. This can increase the risk of re-bleeding and worsen the subconjunctival hemorrhage.
How long do subconjunctival hemorrhages last?
In most cases, it takes about seven to 10 days for a subconjunctival hemorrhage to disappear. During this time, the affected area can change color, like a bruise.
If you don’t see a noticeable improvement within a week, see your eye doctor.
Page published in January 2020
Page updated in January 2022