What causes a broken blood vessel in the eye?
A few days ago, I woke up and noticed that I had what appeared to be bright red blood covering almost half of the white area of my eyeball, and I'm not sure what I did that caused it. My eye didn't hurt, and the blood did not go away when I put eye drops in. I learned that this was likely caused by a broken blood vessel in my eye and that the bloody appearance would fade away over a few days. However, I am concerned about what may have caused my blood vessel to burst. Is this a sign of an underlying medical condition or just one of those things that happens from time to time?
A broken blood vessel in the eye, known medically as a subconjunctival hemorrhage, is a very common and almost always a benign medical problem. However, it is important to get a general check up from a primary care doctor to make sure it's not something serious. The small blood vessels that run below the conjunctiva (the membranous covering of the eye and eyelid) are very fragile. They can be ruptured for many reasons. Obviously direct trauma to the eye can cause the blood vessels to rupture, even extremely minor trauma like rubbing an eye too hard. Many things that cause these delicate blood vessels to rupture involve straining, which temporarily increases blood pressure in veins. And because of this, subconjunctival hemorrhages tend to be a side effect of other problems. Subconjunctival hemorrhages can come along with a cold (which causes a lot of coughing and sneezing), constipation (which causes a lot of straining), childbirth (again, straining), falling or otherwise injuring yourself (people tend to strain very hard as they get injured), GI illness (straining due to vomiting and bowel movements). Other less common causes of subconjunctival hemorrhage are very high blood pressure and problems with blood clotting or increased levels of anticoagulant medication. In your case, a subconjunctival hemorrhage could suddenly appear overnight for these reasons: you rubbed your eye violently in your sleep, you sneezed or coughed hard in your sleep, something happened at the end of the day that caused it and you did not notice it till morning, or (less likely) you have a medical condition like high blood pressure or a blood clotting problem that caused it to occur spontaneously. The hemorrhage itself is harmless and will resolve on its own over a few weeks. Again you should get a general check up from a primary care doctor to make sure you are not developing a problem with high blood pressure or, rarely, blood clotting.
This answer is for general informational purposes only and is not a substitute for professional medical advice.
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