Blood Spot in the Eye (Subconjunctival Haemorrhage): Causes, When to Worry and Treatment
You look in the mirror and one eye has a vivid red patch across the white — no pain, no warning, no obvious reason. It is one of the most frightening things an eye can do, and one of the most common reasons people rush to an eye clinic convinced something serious has happened. The reassuring truth is that a flat red patch on the white of the eye, a subconjunctival haemorrhage, is almost always a harmless burst blood vessel that clears on its own. The skill is in telling this benign blood spot apart from the few red-eye situations that genuinely need attention.
The short answer
A subconjunctival haemorrhage is a small amount of blood trapped just under the clear surface film of the eye — like a bruise on the white of the eye. It usually looks far worse than it is: it does not affect your vision, does not hurt, and does not threaten the eye. Most appear for no clear reason or after a cough, a sneeze or a rub, and they fade over one to two weeks, changing colour like any bruise. The situations that do need prompt attention are different: a red eye with pain, light sensitivity, reduced vision, discharge, or after a real injury — or blood spots that keep coming back.
What a subconjunctival haemorrhage actually is
The white of the eye is covered by a thin, transparent membrane called the conjunctiva, which carries tiny, delicate blood vessels. If one of these vessels breaks, a little blood escapes and spreads out flat underneath the membrane, where it cannot drain away quickly. Because it sits under a clear film, it shows up as a bright red, sharply outlined patch on the white of the eye. The blood is on the surface — it is not inside the eye and not near the part you see with — which is exactly why vision stays perfectly normal.
Why it looks so alarming — but usually is not
A blood spot can cover a large part of the white and can even bulge slightly, so people understandably assume the worst. But a true subconjunctival haemorrhage has a very reassuring signature: it is painless, does not blur vision, produces no discharge, and is not gritty beyond a mild awareness. There is nothing you have done wrong, and the blood cannot “spread into the eye” or damage sight. The colour will actually look worse for a day or two as the blood spreads out before it starts to fade — this is normal.
Common causes: often for no reason at all
In many people a blood spot appears completely spontaneously, with no identifiable trigger. When there is a cause, the usual ones are:
- A sudden pressure surge (Valsalva): hard coughing, sneezing, vomiting, straining on the toilet, or heavy lifting can pop a small vessel.
- Minor trauma or rubbing: vigorously rubbing the eye, a stray finger, or a small knock — and contact-lens handling.
- High blood pressure: particularly in older adults and when blood spots keep recurring.
- Blood-thinning medicines: aspirin, clopidogrel, warfarin and the newer anticoagulants make small bleeds more likely and more visible.
- Other causes: occasionally a bleeding tendency, certain eye infections, after eye surgery or an injection, and in newborns from the pressure of delivery.
How long it lasts and what to expect
A subconjunctival haemorrhage clears by itself. Over roughly one to two weeks (sometimes up to three for a large one) the body reabsorbs the blood, and just like a bruise on the skin it changes colour — from bright red to orange and yellowish — before disappearing completely with no mark and no effect on the eye. You do not need to do anything to make it heal, and there is no drop that clears it faster.
When a red eye is NOT a simple blood spot
The one thing that matters is separating a harmless blood spot from a red eye that needs a doctor. Seek prompt eye care — the warning signs on our emergency eye care page — if the red eye comes with any of these:
- Pain, light sensitivity or any change in vision (a true blood spot has none of these);
- A significant injury or blow to the eye — here the redness can hide a more serious problem inside the eye that must be examined the same day;
- Discharge, stickiness or grittiness, which point to infection or another surface problem rather than a simple bleed;
- Blood that looks like it is inside the coloured part of the eye (a different problem called a hyphema) after trauma;
- Both eyes together, or spontaneous bruising and bleeding elsewhere on the body.
Blood spots that keep coming back
A single blood spot in an otherwise well person needs no tests. But recurrent subconjunctival haemorrhages deserve a short look for an underlying reason — most often blood pressure, and a review of any blood-thinning medication. A quick blood-pressure check and, where relevant, a check for diabetes or a bleeding tendency usually settles the question; recurrent surface fragility can also relate to systemic vascular health, which is one reason a diabetic eye and general eye assessment is worthwhile if spots keep appearing. Two rules matter here: do not ignore repeated bleeds, and never stop a prescribed blood thinner on your own — any change is a decision for the doctor who prescribed it.
Blood spots in newborns and after eye procedures
A red patch on a newborn’s eye, present soon after birth, is common and comes from the pressure of delivery; it clears over one to two weeks like any other blood spot. Similarly, a little visible blood on the white after cataract surgery, an injection or an eye examination is expected and harmless. As always, pain, discharge or a change in the baby’s eye or general wellbeing should be reviewed promptly rather than assumed to be a simple bleed.
How we assess it
Diagnosis is usually made in seconds at the slit-lamp: a flat, bright-red, painless patch with a clear eye behind it and normal vision is a subconjunctival haemorrhage and nothing more. The value of a visit is mostly to confirm it is what it looks like and to exclude the mimics — checking vision, the surface, and the front of the eye, and taking a blood-pressure reading when the history suggests it. This straightforward assessment is part of a routine comprehensive eye check-up, and it is what lets us reassure most people firmly rather than vaguely. Contact-lens wearers with a red, uncomfortable eye need the ocular surface checked to be sure the redness is only a harmless bleed.
Treatment: usually just reassurance
Because a subconjunctival haemorrhage heals on its own, the “treatment” is mostly understanding what it is and waiting it out. Where the eye feels a little gritty, simple lubricating drops ease the surface. A cold compress in the first day or two can limit how far the blood spreads, and gentle warmth later may help it clear. Beyond that, the sensible steps are to avoid rubbing the eye and to address any underlying cause — controlling blood pressure and reviewing (never abruptly stopping) blood thinners with your physician. Antibiotic drops are not needed for a plain blood spot, and no drop makes it vanish faster.
The bottom line
A blood spot on the white of the eye is dramatic to look at and almost always completely harmless — a small burst vessel that fades like a bruise over a week or two, with no effect on vision and no lasting mark. What deserves attention is a red eye that hurts, blurs vision, follows an injury, discharges, or keeps returning. If you are unsure which you have — or if blood spots keep coming back — a two-minute examination will tell you exactly, and usually the message is simple reassurance.
Worried about a sudden red patch on your eye, or getting them repeatedly? Have it checked at Balaji Horizon Eye Hospital, Ahmedabad (Science City & Naranpura). Call +91 92748 67875 or book an appointment online.
Frequently asked questions
Is a blood spot in the eye dangerous?
In almost all cases, no. A subconjunctival haemorrhage is a harmless burst blood vessel on the surface of the eye. It does not affect vision, does not hurt, and clears on its own over one to two weeks. It becomes a concern only if the red eye also has pain, light sensitivity, reduced vision or discharge, or if it follows a real injury — those need a prompt eye examination.
What causes a sudden red spot on the white of the eye?
Often nothing identifiable. When there is a trigger it is usually a pressure surge from coughing, sneezing, straining, vomiting or heavy lifting; rubbing or a minor knock; contact-lens handling; high blood pressure; or blood-thinning medicines such as aspirin or warfarin. Occasionally it relates to a bleeding tendency, and in newborns it can follow the pressure of delivery.
How long does a subconjunctival haemorrhage take to clear?
Usually one to two weeks, and up to about three weeks for a large one. The blood reabsorbs on its own and changes colour like a bruise — from bright red to orange and yellow — before fading completely with no mark. No drops speed this up, so treatment is mainly reassurance and, if the eye feels gritty, simple lubricating drops.
Should I stop my blood thinner if I get a blood spot in my eye?
No — not on your own. Blood thinners such as aspirin, clopidogrel or warfarin can make these harmless surface bleeds more visible, but they are usually protecting you from far more serious problems. Never stop or change a prescribed blood thinner without speaking to the doctor who prescribed it. If you are getting repeated blood spots, mention it so your blood pressure and medication can be reviewed.
When should I see a doctor for a red eye?
See an eye doctor promptly if the red eye is painful, sensitive to light, has any change or blur in vision, produces discharge, or follows an injury or blow to the eye — and if you get subconjunctival haemorrhages repeatedly. A plain, painless blood spot with normal vision is not an emergency, but a quick check confirms it is harmless and looks for a treatable cause such as high blood pressure.
Medically reviewed by Dr. Jayadatt D. Patel, MBBS, MS (Ophthalmology), FCRS — Cornea, Cataract & Refractive Surgeon. Last reviewed: 6 July 2026.
This article is for general education only and is not a substitute for a professional eye examination or personalised medical advice. A painless red patch on the white of the eye is usually harmless, but seek prompt care for a red eye with pain, light sensitivity, reduced vision, discharge, or after an eye injury, and have recurrent blood spots assessed.
This article is for general awareness and does not replace a consultation with an eye specialist.
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Founder & Director of Balaji Horizon Eye Hospital and Consultant Cornea & Refractive Surgeon at C.H. Nagri Eye Hospital, Ahmedabad. Dr. Patel focuses on accurate diagnosis, vision preservation and individualised, ethical care.
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