Sub-Conjunctival Haemorrhage

The white part of the eye (the sclera) is covered by a thin, clear membrane called the conjunctiva, which has a rich blood supply. A sub-conjunctival haemorrhage happens when these tiny blood vessels leak, and a small amount of blood collects between the sclera and conjunctiva.

Because both layers are transparent, this can look alarming — but it isn’t serious, and it won’t affect your sight. It’s actually the same process as bruising elsewhere on the body: just a small bleed between layers of tissue.

The main sign is a very bloodshot eye, sometimes with a feeling of ‘tightness’. It doesn’t need treatment, and the bloodshot look should clear up within 7 to 14 days. As part of your examination, we’ll also check your blood pressure and run a routine diabetes test, just to rule out an underlying cause.

Common causes include coughing, knocking your eye, or rubbing it hard, as well as diabetes, high blood pressure, or blood-thinning medication such as aspirin or warfarin.

That said, most sub-conjunctival haemorrhages happen for no identifiable reason. In most cases it doesn’t mean you have an illness or eye condition — it’s just a small bleed between the sclera and conjunctiva, the same way a bruise is a small bleed between layers of skin.

Because the cause often can’t be pinned down, we’ll still check your blood pressure and run a routine diabetes test as part of the examination, just to be thorough. The bloodshot appearance will typically clear up on its own within 7 to 14 days regardless of the cause.

No, it does not require treatment. As part of your examination we’ll also check your blood pressure and give you a routine test for diabetes. The bloodshot appearance should clear up within 7 to 14 days.

In most cases, no — it does not mean you have an illness or eye condition, and practically all sub-conjunctival haemorrhages occur for no particular reason.