A broken blood vessel in your eye is almost always a subconjunctival hemorrhage, a small bleed that happens when a tiny vessel bursts in the conjunctiva, the clear tissue that covers the white of your eye. It looks alarming (a bright red patch spreading across the white of your eye) but is painless and harmless in most cases. The blood gets trapped between the conjunctiva and the white of the eye, which is why it looks so vivid. Most cases heal on their own within two weeks.
How a Vessel Actually Breaks
The blood vessels in the conjunctiva are extremely small and fragile. They can rupture from even a modest spike in pressure. The most common trigger is a Valsalva maneuver, which is any action where you strain against a closed airway. When this happens, pressure builds in your chest and abdomen, venous return to the heart drops, and blood pressure in peripheral vessels (including the tiny ones in your eye) rises rapidly. Once that strain releases, blood surges back toward the heart, causing another abrupt pressure shift. That combination of pressure spikes is enough to pop a delicate conjunctival vessel.
In everyday life, a Valsalva maneuver happens more often than you’d think. Hard coughing, violent sneezing, vomiting, heavy lifting, straining during a bowel movement, or even intense laughing can all produce it. Some people wake up with a red patch after a night of coughing from a cold and have no idea when it happened.
Other Common Triggers
Rubbing your eyes vigorously is one of the simplest ways to break a vessel, especially if your eyes are dry or irritated. Minor trauma, like getting poked by a finger, a makeup brush, or a contact lens, can do it too. Eye surgery, even routine cataract procedures, sometimes causes a subconjunctival hemorrhage as a side effect.
Less obvious causes include:
- Dry or irritated eyes. Chronic dryness weakens the surface tissue and makes vessels more vulnerable to rupture from minimal contact.
- Contact lens wear. Lenses can create friction against the conjunctiva, especially if they’re old or poorly fitted.
- Allergies. Frequent eye rubbing during allergy season is a common culprit.
Sometimes no clear trigger exists at all. Spontaneous subconjunctival hemorrhages are common and can happen while you’re sleeping or doing nothing strenuous.
Health Conditions That Increase the Risk
High blood pressure is one of the biggest underlying risk factors. Chronically elevated pressure puts extra stress on small blood vessels throughout the body, including the ones in your eye. If you’re getting recurrent broken blood vessels and haven’t had your blood pressure checked recently, that’s worth looking into.
Diabetes damages blood vessels over time, making them more fragile and prone to rupture. Bleeding disorders or clotting problems can also make it easier for small vessels to break and harder for the bleeding to stop quickly once it starts. Chronic inflammatory conditions affecting the eye, such as uveitis, have been linked to a higher rate of these hemorrhages as well.
Medications That Make It More Likely
Blood thinners are a well-known risk factor. Warfarin, aspirin, and newer oral anticoagulants all increase the chance of a subconjunctival hemorrhage because they slow your blood’s ability to clot. One large review of over 100,000 patients found that among the newer anticoagulants, edoxaban carried a lower risk of eye bleeding compared to warfarin, while others like rivaroxaban and dabigatran showed similar risk profiles to warfarin.
If you’re taking a blood thinner and notice a broken vessel, it’s not necessarily a reason to stop your medication, but it’s worth mentioning to your prescriber, especially if it keeps happening. One study found that patients who stayed on aspirin or warfarin around the time of cataract surgery had a 10% higher rate of subconjunctival hemorrhage compared to those who paused their medication beforehand.
Long-term use of steroid eye drops can also weaken blood vessels in the conjunctiva. Prednisolone acetate 1% was the most commonly associated steroid in patients who developed this problem. Over-the-counter anti-inflammatory drugs like ibuprofen and naproxen carry a smaller but real risk as well, since they affect platelet function.
What Recovery Looks Like
Most subconjunctival hemorrhages clear up within two weeks without any treatment. The blood can’t go anywhere quickly because it’s trapped under the conjunctiva, so your body reabsorbs it gradually. Over that period, the bright red patch will shift in color much like a bruise, fading through darker shades before taking on a yellowish tint as the last of the blood is cleared away.
There’s nothing you need to do to speed the process along. Artificial tears can help if the area feels mildly irritated or scratchy, but the hemorrhage itself doesn’t hurt. Avoid rubbing the eye while it heals, and if you’re taking blood thinners, the clearing process may take a bit longer.
When a Red Eye Is Something More Serious
A standard subconjunctival hemorrhage is painless and doesn’t affect your vision. If you have pain, blurred vision, or sensitivity to light alongside the redness, something else may be going on.
The condition most often confused with a broken vessel is a hyphema, which is bleeding inside the eye rather than on its surface. With a hyphema, blood collects in the front chamber of the eye, right in front of the iris (the colored part). It looks like blood is pooling where your eye color is, not across the white. Hyphema causes pain, can blur or distort your vision, and sometimes triggers nausea or vomiting if pressure inside the eye climbs too high. It can lead to dangerously elevated eye pressure, glaucoma, and even permanent vision loss if untreated. A hyphema almost always follows an injury or trauma and needs prompt medical attention.
A single, painless subconjunctival hemorrhage after a coughing fit or a rough sneeze is nothing to worry about. But if broken vessels keep recurring, especially without an obvious cause, that pattern can signal an underlying issue like uncontrolled high blood pressure, a clotting disorder, or a medication side effect that needs adjusting. Recurrent episodes are worth bringing up with your doctor so they can check your blood pressure and, if you’re on a blood thinner, confirm your dosing is in the right range.