What causes burst blood vessels in the eye?

Posted on

23 February 2021

Author: Kate Green

burst blood vessel

Triggers for a burst blood vessel


Have you ever looked in the mirror and been shocked to find a bright red spot of blood in the white part of your eye? The name for this is a subconjunctival haemorrhage. Although it can be quite alarming initially due to its vivid appearance, it’s important to know that it’s usually nothing to worry about. In fact, most of the time, subconjunctival haemorrhages disappear within a couple of weeks without treatment, gradually fading as a bruise would.


The conjunctiva is a thin clear layer on top of the white part of your eye (the sclera). It has lots of tiny, thin blood vessels in it and, if these break, the blood leaks out and sits between the conjunctiva and the sclera. This is because the conjunctive can’t absorb blood very quickly. The size of your subconjunctival haemorrhage depends on the amount of blood which has leaked out. Often, it will just look like a small spot of blood but, when there has been a big leak, the red area may take up your entire sclera, or even bulge outwards.


You shouldn’t experience any pain but you may have a slight scratching sensation. The spot of blood may grow over the first 24-48 hours as the blood continues to bleed out of the conjunctiva.


A burst blood vessel in the eye can be caused by a number of actions:

  • Sneezing
  • Coughing
  • Straining
  • Vomiting
  • Eye injuries
  • Viral infection
  • Contact lenses


Who is most at risk of having burst blood vessels in the eye?


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Subconjunctival haemorrhages are more likely as you get older. Further to this, a total subconjunctival haemorrhage could be a sign of serious heart disease in older people. If you fall into this category and you have a large patch of blood in your eye, it’s a good idea to see your doctor for a check-up.


Aspirin and warfarin can affect your blood’s ability to clot, which leads to a higher risk of burst blood vessels in the eye. If you take medication like this, it could mean that you experience subconjunctival haemorrhages more frequently than other people, and that the size of them is much larger than normal.


On top of these points, high blood pressure is also a risk factor for burst blood vessels, as well as having diabetes. Ensuring that you eat a healthy diet to keep your blood pressure as low as possible could help prevent complications from severe subconjunctival haemorrhages.


When should I seek help for a burst blood vessel in the eye?


With most subconjunctival haemorrhages, you shouldn’t experience any visual changes, nor any pain. If you find yourself struggling with either of these, you should see your optician as soon as possible. You should also seek help for your burst blood vessel if it doesn’t disappear within two to three weeks, or if the blood seeps into your iris (the brown, blue, or green coloured part of your eye) coloured part of your eye. This, as well as having more than one subconjunctival haemorrhage, could be an indication of something more serious.

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For most people, subconjunctival haemorrhages are a rare occurrence so, if you experience one more than twice a year, you should also book a check-up appointment, just to check it’s not an sign of something more sinister.


How can I prevent a burst blood vessel in the eye?


Often, burst blood vessels in the eye are caused by accidentally hitting yourself in the eye as you sleep at night. This is tricky to avoid as it’s something that you don’t do deliberately, but there are a few things you can do to minimise your likelihood of developing a subconjunctival haemorrhage:

  • Take care of your contact lenses
  • Maintain a healthy blood pressure
  • Rub your eyes gently


If you do go to the opticians for a check-up and let them know about your subconjunctival haemorrhage, they will likely dilate your eyes to examine inside of them. This allows them to check for any trauma deeper inside the eye causing the subconjunctival haemorrhage. Your optician should also be able to provide any moisturising eye drops if your eye feels gritty or itchy with a subconjunctival haemorrhage.


Taking steps towards living a healthy lifestyle including a good diet, regular exercise, and not smoking or drinking excessively should help your overall eye health, including reducing the development of subconjunctival haemorrhages.

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