Blood in the White of Your Eye - Subconjunctival Haemorrhage

Common questions

Why is there blood in the white of my eye?

What you are seeing is a subconjunctival haemorrhage - a small blood vessel has broken under the conjunctiva, the thin clear membrane that covers the white of the eye. Blood has nowhere to go once it is under that membrane, so instead of forming a raised bruise the way it would under skin, it spreads out flat - bright red against white makes even a small amount look larger than it is. There is usually no pain, no discharge, and no effect on your vision, because the bleeding sits on the surface and does not involve the eye itself.

Is a subconjunctival haemorrhage dangerous?

On its own, no. It is one of the most alarming-looking things that can happen to an eye and one of the least serious - a cosmetic event, not a threat to your vision, that resolves by itself with no treatment. The exceptions worth knowing: trauma, both eyes bleeding at once, the same eye bleeding repeatedly, or any pain or change in vision alongside the redness. If there was trauma - especially anything that could have struck or penetrated the eye - go to an emergency department rather than waiting to get it examined. Any of the other exceptions is a reason to get the eye examined.

How long does blood in the eye take to clear?

Most subconjunctival haemorrhages clear on their own over roughly one to three weeks. The blood behaves like a bruise under skin, changing colour as it resorbs - the bright red patch gradually fades through green and yellow before the eye returns to normal. It typically looks most alarming in the first day or two and improves steadily after that. Nothing needs to be done to speed it along, and no drop or medication will clear it faster.

What causes a broken blood vessel in the eye?

Anything that briefly raises pressure in the eye’s small vessels can cause one to break - coughing, sneezing, straining, vomiting, and forceful eye rubbing are common triggers. Minor trauma, even a poke from a finger or a mascara wand, can also cause it. Blood thinners and high blood pressure make these vessels more likely to break and can make the resulting patch larger. Often there is no trigger you can point to at all - the vessel simply breaks on its own, sometimes noticed only in a mirror or pointed out by someone else.

When should I worry about blood in my eye?

Go to an emergency department if the eye was struck with force - a ball, an elbow, a fall, a tool - if anything may have penetrated it, if a fragment came off grinding or hammering, or if the blood sits in front of the coloured part of the eye rather than over the white. Blunt force can cause damage inside the eye that is not visible from the outside, and that needs imaging a clinic cannot do. A minor poke, such as a fingernail or a mascara wand, is a common cause of an ordinary broken blood vessel and does not need an emergency department - call us instead. Also call us if both eyes are bleeding at once, if the same eye has bled this way before, or if there is pain or any change in your vision along with the redness. A subconjunctival haemorrhage with none of those features almost always turns out to be harmless - but if you are not sure, a same-day look at the eye settles it far better than watching and wondering.

Why does it keep happening?

A single subconjunctival haemorrhage usually needs no follow-up. Recurrence is different, and it is the sign most worth acting on: when the same eye bleeds this way more than once, it can point to something worth reviewing with a physician, most often blood pressure or a blood thinner affecting how easily these small vessels break. That review is about your general health rather than the eye itself, and it is worth having - not because a recurring haemorrhage is dangerous by itself, but because it can be an early sign worth knowing about.

Can I still wear my contact lenses?

If your eye is comfortable with no pain, irritation, or change in vision, a subconjunctival haemorrhage on its own does not usually stop you from wearing contact lenses. If the eye feels irritated, or you are not sure what you are looking at, switching to glasses until it is assessed or has cleared is reasonable. Mention it at your next visit either way.

Related

• Red eye - optometrist, walk-in clinic, or emergency room? - a different kind of red eye, and how to tell them apart
• Urgent eye problems - optometrist vs ER - when to call, when to go to emergency
• Floaters and flashes - when to worry - a different urgent symptom and when it needs same-day care
• Do I need an appointment? - how walk-ins and urgent problems are handled