Blood Spot in the Eye: Subconjunctival Bleed, Scary but Mild?
Verdict: scary to look at, usually mild. A bright red patch on the white of the eye, with no pain and normal vision, is most often a subconjunctival haemorrhage: a tiny burst vessel under the eye’s clear skin. It fades by itself in one to two weeks. Pain, injury or any change in sight is a different story and needs care the same day.
Before you panic
- What it is: blood trapped under the conjunctiva, the thin clear layer over the white of the eye
- Common triggers: a hard cough or sneeze, vomiting, straining on the toilet, lifting heavy things, rubbing the eye
- Usual course: bright red, then orange or yellow at the edges, gone in about 1 to 2 weeks
- Worth checking: your blood pressure, and your doctor’s advice if you take blood thinners or it keeps happening
- Same-day care: injury, pain, vision change, light sensitivity, or blood in the coloured part of the eye
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You glance in the mirror after a bad night of coughing and half the white of one eye is scarlet. It looks alarming. Family members gasp. Yet the eye doesn’t hurt, you can see perfectly, and it only feels a little full or scratchy. This is one of the most common “emergencies” that turns out not to be one.
What a blood spot in the eye actually is
The white of your eye is covered by a see-through skin, the conjunctiva, that carries a mesh of very thin blood vessels. When one of them pops, the blood has nowhere to go. It spreads flat under that clear skin, like red ink under cling film. Because the skin is transparent, even a tiny amount of blood looks dramatic.
The blood isn’t inside the eyeball. It’s on the outside, sitting under the surface layer, which is why vision stays normal. Your body soaks it up slowly, just as a bruise on the arm goes from purple to green to yellow.
Why it happens: coughing, straining and rubbing
A sudden rise in pressure in the head is the usual trigger. That’s why it so often turns up after:
- A coughing fit, whooping cough in children, or a big sneeze
- Vomiting
- Straining with constipation
- Lifting something heavy while holding your breath
- Rubbing the eye hard, or a contact lens mishap
- Childbirth, for the mother and sometimes the newborn
Sometimes there’s no trigger at all. You wake up and it’s there. That’s also common, especially with age, as small vessels get more fragile.
Blood pressure, diabetes and blood thinners
High blood pressure doesn’t usually cause the spot directly, but it’s found often enough in people who get one that checking your BP is sensible. Think of it as a free reminder. A home reading of about 135/85 or above, or a clinic reading of 140/90 or above, is worth taking to a doctor. A reading of 180/120 or higher with headache, chest pain, breathlessness, weakness or blurred vision is an emergency. Our home BP check guide shows how to take a reading you can trust, and high blood pressure and weight covers what brings those numbers down day to day.
Diabetes can make small vessels more fragile too, so keep up with your yearly eye check.
People on blood thinners (warfarin, the newer anticoagulants, or antiplatelet medicines) get these spots more easily. Never stop or skip a blood thinner because of a red eye. Stopping suddenly can bring on a stroke or clot. Tell the doctor who prescribes it; they may check your INR if you take warfarin, and they decide whether anything should change.
What to do at home
- Check it’s painless and your vision is normal in that eye: cover the other eye and read a line of small print.
- Take your blood pressure if you have a machine, sitting quietly for 5 minutes first.
- Leave it alone. Don’t rub. The patch may spread a little over the first day or two; that’s normal.
- For scratchiness, preservative-free lubricating drops (artificial tears) can make it feel more comfortable.
- Rest the contact lenses until the patch clears.
- Deal with the trigger: see a doctor about a lingering cough, and ease constipation with water and fibre.
- Take a phone photo every few days so you can see it fading.
A cold compress on the first day may soothe, but it won’t speed up clearing much. There’s no drop that makes the blood vanish faster.
In many homes a red eye meant rose water, a drop of breast milk or a pinch of surma. None of these clear the blood, and anything put into the eye can bring an infection. The old instinct to rest and not rub, though, is exactly right.
Myth: a red patch means bleeding inside the brain or eye
Not on its own. A flat, painless red patch with normal sight is on the surface. The warning signs are different: severe headache, confusion, weakness on one side, or blood you can see in the coloured part of the eye (hyphaema), which settles as a red line at the bottom of the iris. Those need emergency care.
When a blood spot keeps coming back
One spot every few years is usually just bad luck. If they happen again and again, or you also notice easy bruising, bleeding gums or nosebleeds, see a doctor. They may check your blood pressure, blood count and clotting, and look at your medicines as a whole. The Eye Care section has more on red and irritated eyes.
The red eye followed a blow, a fall, a flying chip or a chemical splash; the eye hurts; your vision is blurred, doubled or dim; light hurts; there’s discharge; the red covers the coloured part of the eye; or you have a severe headache. Also get urgent help for a blood spot in a baby or young child without an obvious cause like a coughing fit, and for anyone on blood thinners with other unusual bleeding. Blood pressure of 180/120 or above with symptoms is an emergency.
Common questions about a blood spot in the eye
How long does a subconjunctival haemorrhage take to go away?
Usually 1 to 2 weeks. A large one can take up to three. It fades from red to orange to yellow, like a skin bruise.
Is a burst blood vessel in the eye serious?
Usually not, if it’s painless and your sight is normal. It becomes a concern with injury, pain, vision change or repeated episodes.
Can high blood pressure cause a blood spot in the eye?
It can be linked, which is why a BP check is sensible. Take a proper reading at home or at a clinic, and see a doctor if it’s 140/90 or higher at the clinic or about 135/85 or higher at home.
I take blood thinners. Should I stop them?
No. Never stop a blood thinner on your own; that can cause a stroke or clot. Tell your prescribing doctor, who decides whether any test or change is needed.
Which eye drops remove blood from the eye?
None speeds it up much. Lubricating drops can ease scratchiness. Avoid “redness relief” drops, which only squeeze surface vessels and do nothing for trapped blood.
Is a red spot in the eye contagious?
No. It’s a small bleed, not an infection. A red eye with sticky discharge and itching is more likely conjunctivitis, which is different.
Can I go to work or school with a blood spot in the eye?
Yes. It isn’t infectious and doesn’t need time off, although it may draw comments.
Can diabetes cause blood in the white of the eye?
Diabetes makes small vessels more fragile, so it may play a part. More important is the yearly retina check, since diabetic eye damage happens inside the eye where you can’t see it.
Why does my eye bleed after coughing or vomiting?
Hard coughing and vomiting briefly raise pressure in the head, and a tiny vessel on the eye’s surface can burst. Getting the cough checked helps stop it happening again.
Should a newborn with red spots in the eyes see a doctor?
Small spots after a normal birth are common and fade in a couple of weeks, but mention them at the baby’s check. A red eye in an older baby without a clear reason needs to be seen promptly.