A subconjunctival haemorrhage is bleeding underneath the conjunctiva. It can occur after a sudden or severe sneeze or cough, heavy lifting, straining, vomiting or even rubbing one’s eyes too roughly. It can also occur as a side effect of eye surgery or blood thinners. It can look very scary and alarming, but it’s usually harmless.
It appears as a bright red patch on the white part of the eye. Its borders are clearly defined, meaning you can see where it ends. Treatment is usually unnecessary as the blood generally reabsorbs in two weeks. If the entire eye is blood red and you cannot see any of the white part, please consult immediately.