A burst blood vessel in the eye is almost always a subconjunctival hemorrhage, a harmless condition where a tiny blood vessel breaks in the clear tissue covering the white of your eye. The blood leaks between this tissue (the conjunctiva) and the white surface beneath it, creating a bright red patch that looks alarming but typically causes no pain and no vision changes. Most cases heal on their own within two weeks.
How It Happens
The conjunctiva is packed with fragile, hair-thin blood vessels. When one ruptures, blood pools in the space between the conjunctiva and the white of the eye. Because the conjunctiva is transparent, you see the blood clearly, which is why even a small amount looks dramatic. The blood isn’t absorbed right away. Instead, it spreads beneath the surface and gradually fades over days, often shifting from red to yellow before disappearing entirely.
Physical Triggers
The most common cause is a sudden spike in pressure inside your body. Any action that makes you bear down, hold your breath, or strain can force blood through the walls of these delicate vessels. Doctors call this the Valsalva maneuver, and it happens more often than you’d think.
Common physical triggers include:
- Violent coughing or sneezing
- Vomiting
- Heavy lifting or straining during exercise
- Straining during a bowel movement
- Childbirth (labor and pushing)
- Blowing a musical instrument
- Sexual activity
The mechanism is straightforward: these activities raise pressure in the chest or abdomen, which backs up venous pressure into the upper body, including the tiny vessels in the eye. The weakest capillaries give way first.
Eye Rubbing and Minor Trauma
Rubbing your eyes aggressively is one of the most overlooked causes. Even a minor bump, a foreign body grazing the surface, or inserting and removing contact lenses can rupture a vessel. Contact lens wearers face a slightly higher risk, particularly if they have pre-existing changes to the conjunctival tissue. Research has found that people with loose, redundant conjunctival tissue or small yellowish growths on the white of the eye are more prone to lens-related hemorrhages, with bleeding most commonly appearing on the outer (temple) side of the eye.
Medical Conditions That Weaken Blood Vessels
Sometimes a burst vessel reflects something going on beneath the surface. High blood pressure is one of the most significant contributors because sustained pressure damages small blood vessel walls throughout the body, including in the eye. Diabetes has a similar effect over time, making capillary walls more fragile and prone to spontaneous rupture.
Bleeding disorders, whether inherited or acquired, can also cause recurrent episodes. If your blood doesn’t clot efficiently, even normal eye movements or minor friction can produce visible bleeding. People who experience subconjunctival hemorrhages repeatedly without an obvious trigger may benefit from a blood workup to check for clotting abnormalities.
Medications That Raise Risk
Blood thinners and antiplatelet medications are a well-established risk factor. A study from the Cole Eye Institute found that subconjunctival hemorrhage was the most common type of eye bleeding in patients on these drugs, accounting for 51% of all ocular bleeding events. Nearly half of the patients who experienced spontaneous bleeding were also taking aspirin alongside their primary blood thinner.
You don’t need to be on a prescription blood thinner for this to apply. Over-the-counter aspirin and common supplements like fish oil and vitamin E also reduce clotting ability. If you’re taking any combination of these, your threshold for a burst vessel is lower than average.
When It’s Not Just a Burst Vessel
A standard subconjunctival hemorrhage is painless. The red patch sits on the white of the eye, your vision stays normal, and the only symptom might be a mild scratchy sensation. If your experience is different from this, something more serious could be going on.
A hyphema is bleeding inside the eye itself, between the cornea and the colored part of your eye (the iris). Unlike a subconjunctival hemorrhage, a hyphema causes pain, blurred or distorted vision, and sometimes nausea or vomiting from dangerously high pressure inside the eye. The blood appears to pool in front of the iris rather than on the white surface. A hyphema is a medical emergency, usually caused by direct trauma to the eye.
Seek immediate care if you notice blood in front of your iris, any vision changes, eye pain, bleeding in both eyes at once, or bleeding that follows a hard impact to the face or head.
Healing and What to Expect
Most subconjunctival hemorrhages clear completely within two weeks. Larger spots may take longer. There’s no way to speed up the process. The body reabsorbs the trapped blood at its own pace, and the red patch will likely change color as it fades, similar to a bruise on your skin.
No treatment is needed in most cases. If the area feels irritated or scratchy, over-the-counter artificial tears can help with comfort. Avoid rubbing the eye, which can worsen bleeding or delay healing. If you’re on blood thinners, don’t stop taking them because of a burst vessel. That’s a decision that should involve your prescriber.
Recurrent Episodes
A single episode is rarely worth investigating beyond a quick look. But if burst vessels keep happening, especially without a clear trigger like heavy lifting or a coughing fit, that pattern can signal uncontrolled blood pressure, a clotting disorder, or a medication side effect that needs review. Keeping track of how often it occurs and what you were doing beforehand gives your doctor useful information for deciding whether bloodwork or a blood pressure check is warranted.