A bright red patch on the white of your eye is almost always a subconjunctival hemorrhage, a tiny broken blood vessel just beneath the clear surface membrane. It looks alarming but is usually painless and harmless. Most cases heal on their own within two weeks without any treatment.
That said, not every type of blood in the eye is harmless. Where the blood sits, whether you have pain, and whether your vision has changed all matter when figuring out what’s going on.
The Most Common Cause: A Broken Blood Vessel
The conjunctiva is a thin, clear membrane covering the white of your eye. It contains tiny, fragile blood vessels that can rupture easily, spilling a small amount of blood that gets trapped beneath the surface. The result is a vivid red spot, sometimes covering a large portion of the white of your eye, that you typically notice in the mirror without having felt a thing.
Common triggers include coughing, sneezing, straining (like during heavy lifting or a hard bowel movement), vomiting, rubbing your eye, or a minor bump to the eye area. Sometimes there’s no identifiable trigger at all. Even a strong sneeze is enough to burst one of these vessels.
A subconjunctival hemorrhage doesn’t affect your vision, doesn’t hurt, and doesn’t need treatment. If the area feels mildly irritated, artificial tears can help. As the blood clears over the following days, the color shifts like a fading bruise, sometimes taking on a yellowish tint before fully resolving. Larger spots can take several weeks to disappear completely.
When Blood Pools Inside the Eye
A hyphema is a different situation entirely. Instead of blood sitting on the surface of the white of your eye, blood collects in the front chamber of the eye, the fluid-filled space between the cornea and the iris (the colored part). You might notice a visible layer of blood pooling in the lower part of your iris, or your vision may simply look cloudy or distorted.
The key differences from a simple broken blood vessel: a hyphema causes pain and affects your vision. It’s typically caused by a direct blow to the eye, such as a sports injury, a fall, or an accident. A hyphema needs prompt medical attention because the pooling blood can raise pressure inside the eye and damage your vision if left untreated.
Scratches and Foreign Objects
A corneal abrasion, a superficial scratch on the clear front surface of the eye, can cause redness that looks like bleeding. Dust, dirt, sand, metal particles, contact lenses, and even the edge of a piece of paper can scratch the cornea. The redness from an abrasion usually comes with sharp pain, tearing, and a feeling that something is stuck in your eye. Unlike a subconjunctival hemorrhage, a scratch won’t produce a distinct red patch. Instead, the eye looks broadly red and irritated.
Risk Factors That Make Bleeding More Likely
Some people get subconjunctival hemorrhages repeatedly, and certain health conditions make that more likely. High blood pressure is a significant one. Elevated blood pressure increases the risk of small vessels rupturing, not just in your eye but throughout your body. If you’re getting frequent eye bleeds, uncontrolled blood pressure may be the underlying reason.
Blood-thinning medications, including common over-the-counter options like aspirin, reduce your blood’s ability to clot and make it easier for small bleeds to occur and persist. Bleeding disorders, liver disease, and kidney problems can also slow clotting and contribute to recurring episodes. If subconjunctival hemorrhages keep happening, your eye doctor will likely want to investigate these possibilities with further testing.
What Healing Looks Like
Most subconjunctival hemorrhages follow a predictable pattern. The bright red patch gradually shifts color over about two weeks, moving through darker reds and browns before developing a yellowish tint as the last traces of blood are reabsorbed. Think of it like a bruise on your skin going through its color stages. Larger hemorrhages simply take longer, sometimes stretching to three or four weeks before fully clearing.
There’s no way to speed the process up. The blood has to be reabsorbed naturally. Rubbing the eye or straining during recovery could potentially trigger a new bleed in the same area, so it’s worth being gentle.
Signs That Need Prompt Attention
A painless red patch with normal vision is rarely an emergency. But certain combinations of symptoms point to something more serious:
- Pain in the eye suggests blood may be pooling inside the eye (hyphema) rather than on the surface, or that there’s an injury to deeper structures.
- Blurred or distorted vision alongside the redness indicates something beyond a simple surface bleed.
- A direct blow to the eye that preceded the bleeding warrants an exam even if you feel fine, since internal damage isn’t always immediately obvious.
- Frequent recurrences without a clear trigger like coughing or sneezing may signal an underlying issue with blood pressure, clotting, or, in rare cases, conditions like vascular malformations or deposits of abnormal proteins in the conjunctival tissue.
In any of these scenarios, an eye doctor can examine the structures of the eye using a magnifying slit-lamp microscope and check the pressure inside the eye to rule out damage. For surface hemorrhages that keep coming back, further blood work or blood pressure monitoring can help identify the root cause.