Waking up to a blood-red eye: subconjunctival haemorrhage, and how we see you the same day

Few things send people to the mirror in alarm faster than an eye that has turned deep red overnight. The most common cause is a subconjunctival haemorrhage — a burst blood vessel under the clear skin of the eye — and in most cases it looks far worse than it is: typically painless, harmless to vision, and it clears on its own. But "most cases" is doing real work in that sentence, which is why we check. The photograph above is from our clinic: a dense haemorrhage that was painless, with normal vision, and resolved without treatment.

What has actually happened

The conjunctiva carries a network of fine blood vessels. When one leaks, the blood has nowhere to go — it pools between the layers like a bruise under a fingernail. Common triggers include a burst of pressure (coughing, sneezing, straining, heavy lifting), vigorous eye rubbing, minor knocks, contact lens handling, blood-thinning medication, or high blood pressure. Often no cause is ever found. Like any bruise it changes colour — red to orange-yellow — and fades over one to three weeks. No drop speeds it up; lubricants can ease mild grittiness.

Why we still want to see it

The check matters more than the treatment. At an acute visit we examine the eye on the slit lamp to confirm the blood is truly in front of the white of the eye and the surface beneath is intact, check vision and eye pressure, and rule out the conditions that mimic a simple haemorrhage — inflammation, infection or injury to the eyeball itself. When haemorrhages keep recurring, we will suggest a blood pressure check with your GP and a medication review if you are on blood thinners — sometimes the eye is the messenger, not the problem.

A red eye is NOT routine when…

The eye is painful (aching, deep or severe — not just gritty); your vision has changed; you are sensitive to light; there is discharge, or you wear contact lenses and the eye is red and sore; or it followed a significant injury to the eye or head. Any of these, same day, no waiting: ring 07 847 3195.

How acute care works at Rose

We keep acute slots in every clinic day precisely for this. Phone first — a human triages urgency better than a calendar — and we will tell you honestly whether you need to be seen within the hour, today, or not at all. As therapeutic optometrists we can diagnose and, where needed, prescribe treatment on the spot, photograph the eye so there is a baseline to compare against, and refer directly to Hamilton's ophthalmologists on the rare occasion a red eye needs a surgeon. Most subconjunctival haemorrhages need nothing but reassurance — and reassurance based on an examination is worth far more than reassurance based on a guess.

Red eye this morning?

Ring 07 847 3195 and we will fit you in, or book an acute appointment (new patient) / acute appointment (existing patient).

Frequently asked questions

Why is my eye red?

A painless, sharply defined sheet of red is usually a subconjunctival haemorrhage — alarming to look at but generally harmless. Red eyes with pain, light sensitivity, discharge or blurred vision have different causes and need same-day assessment.

What causes a burst blood vessel in the eye?

Common triggers include a spike of pressure from coughing, sneezing, straining or lifting; eye rubbing; minor knocks; contact lens handling; blood-thinning medication; and high blood pressure. Often no cause is found.

How do you treat a burst blood vessel in the eye?

No drop speeds the blood's clearance — like a bruise it fades over one to three weeks. Lubricants ease mild grittiness. The value of a visit is the check: confirming nothing more serious sits behind the blood.

When should I see someone about a red eye?

Same day if there is pain beyond grittiness, any change in vision, light sensitivity, discharge, a red sore eye in a contact lens wearer, or a significant knock. Ring 07 847 3195 and we will triage you honestly.