Subconjunctival hemorrhage (broken blood vessel in eye)
Overview
A subconjunctival hemorrhage (sub-kun-JUNK-tih-vul HEM-uh-ruj) occurs when a tiny blood vessel breaks just underneath the clear surface of your eye (conjunctiva). In many ways, it's just like having a bruise on your skin. The conjunctiva can't absorb blood very quickly, so the blood gets trapped. You may not even realize you have a subconjunctival hemorrhage until you look in the mirror and notice that the white part of your eye is bright red.
A subconjunctival hemorrhage often occurs without any obvious harm to your eye. Even a strong sneeze or cough can cause a blood vessel to break in the eye. You don't need to treat it. A subconjunctival hemorrhage may look alarming, but it's usually a harmless condition that disappears within two weeks or so.