Eye conditions
What is a sub-conjunctival haemorrhage?
A sub-conjunctival haemorrhage is a small bleed on the surface of your eye. It can look alarming, but it isn’t serious and it won’t affect your sight.
The white of your eye (the sclera) is covered by a thin, clear layer called the conjunctiva, which has lots of tiny blood vessels. When one of these leaks, a small amount of blood collects between the two layers. Because both are see-through, it shows up as a bright red patch.
It’s the same process as a bruise, which is a small bleed between layers of skin. It doesn’t need treatment and usually clears up on its own within 7 to 14 days.
Know the signs
Symptoms and causes
Symptoms
- A bright red patch on the white of your eye, which can cover a large area
- It appears suddenly, and you may only notice it when you look in a mirror
- It's usually painless
- Your eye may feel tight or gritty
- Your sight isn't affected
Causes
Most happen for no clear reason. When there is a cause, it can be:
- Coughing, sneezing or straining
- Knocking your eye, or rubbing it very hard
- Recent eye surgery
What can make it more likely?
You may be more likely to have one if you:
- Have high blood pressure
- Have diabetes
- Take blood-thinning medicine, such as aspirin or warfarin
- Are older, as they become more common with age
Get it checked
When to get help
A sub-conjunctival haemorrhage doesn’t need treatment, and you don’t usually need to go to hospital. Book an appointment with us, or see your GP, if:
- You're not sure what's causing the red patch
- It hasn't cleared up within two weeks
- It keeps happening, or you bruise easily elsewhere on your body, especially if you take aspirin or warfarin
- It happened after a knock to your eye
Get urgent help if:
- Your eye becomes painful
- Your sight is blurred or reduced
- The red patch gets very large or keeps spreading
- It follows a serious eye injury
- If you have any of these, contact eye casualty, go to A&E or call NHS 111
Healing
What to expect
A sub-conjunctival haemorrhage heals on its own, in the same way as a bruise. Most clear within 7 to 14 days, though a large one can take up to 3 weeks.
It may spread
The red patch can look as if it's getting bigger for the first few days before it starts to improve.
It changes colour
Like a bruise, the patch can fade and turn slightly yellow as your body absorbs the blood.
It clears
Most have gone completely within 7 to 14 days. A large one can take 2 to 3 weeks.
Is it serious? In most cases, no. Practically all sub-conjunctival haemorrhages happen for no particular reason, and it doesn’t mean you have an illness or eye condition.
Good to know
Can I carry on as normal?
Yes. You can carry on with your normal activities while it heals, including work and school. It isn’t infectious, so it won’t spread to other people.
Treatment
Your appointment and treatment
A sub-conjunctival haemorrhage doesn’t need treatment. If you’re worried, we can check your eye, confirm what’s causing the redness and look for anything that might have triggered it.
What we check
Your eye
We examine your eye to confirm it's a sub-conjunctival haemorrhage and rule out other causes of a red eye.
Your blood pressure
High blood pressure can be a cause, so we'll check your blood pressure as part of your appointment.
Diabetes
Diabetes can make a bleed more likely, so we'll also give you a routine test for diabetes.
Easing discomfort
You don’t need any treatment, and the red patch will fade on its own. It may feel a little tight or gritty while it heals.
- Lubricating eye drops from a pharmacist can help if your eye feels gritty or uncomfortable
- Try not to rub your eye
Read our guide to using eye drops.
If you take blood thinners
Blood-thinning medicines such as aspirin or warfarin can make a sub-conjunctival haemorrhage more likely.
Don’t stop taking your medicine because of a red patch on your eye. But if you get them often, or you notice bruising elsewhere on your body, speak to your GP, who may arrange further tests.
FAQs
Frequently asked questions about sub-conjunctival haemorrhage
What is a sub-conjunctival haemorrhage?
The white part of your eye (the sclera) is covered by a thin, clear layer called the conjunctiva, which has lots of tiny blood vessels. A sub-conjunctival haemorrhage happens when one of these leaks and a small amount of blood collects between the two layers. It looks alarming, but it isn’t serious and it won’t affect your sight.
What causes a sub-conjunctival haemorrhage?
Most happen for no clear reason. Possible causes include coughing, sneezing or straining, knocking or rubbing your eye hard, and recent eye surgery. High blood pressure, diabetes and blood-thinning medicines such as aspirin or warfarin can make one more likely.
Does a sub-conjunctival haemorrhage need treatment?
No. It clears up on its own, usually within 7 to 14 days. If your eye feels gritty or uncomfortable, lubricating eye drops from a pharmacist can help. If you come to see us, we’ll also check your blood pressure and give you a routine test for diabetes.
Is a sub-conjunctival haemorrhage a sign of a serious eye condition?
In most cases, no. Practically all sub-conjunctival haemorrhages happen for no particular reason, and it doesn’t mean you have an illness or eye condition.
How long does it take to go away?
Most clear within 7 to 14 days, though a large one can take up to 3 weeks. It may seem to spread for the first few days, and it can turn slightly yellow as it fades, like a bruise.
Will it affect my sight?
No. A sub-conjunctival haemorrhage sits on the surface of your eye, so it shouldn’t affect your vision. If your sight becomes blurred or reduced, contact eye casualty or call NHS 111.
Is it contagious?
No. It’s a small bleed, not an infection, so it can’t spread to other people. You can carry on with your normal activities, including work and school.
Should I stop taking aspirin or warfarin?
No, don’t stop taking any prescribed medicine because of a sub-conjunctival haemorrhage. If you get them often, or notice bruising elsewhere on your body, speak to your GP, who may arrange further tests.
When should I get it checked?
Book an appointment if you’re not sure what’s causing the redness, it hasn’t cleared within two weeks, it keeps happening, or it followed a knock to your eye. Get urgent help if your eye becomes painful, your sight is affected or the red patch gets very large.
Medically reviewed by Amar-Kaash Gandecha, BSc(Hons) MCOptom DipTp(IP), Prof Cert Glauc, Director and Optometrist. Last reviewed 14 August 2026.
Noticed a red patch on your eye?
It’s usually nothing to worry about, but if you’re not sure, book an appointment at our Newark, Anstey, Birstall or Sileby practice. If your eye is painful or your sight is affected, get help straight away.