When small, delicate blood vessels break beneath the tissue covering the white of the eye (conjunctiva), resulting eye redness may mean that you have a subconjunctival haemorrhage.
A subconjunctival haemorrhage usually is benign, causing no vision problems or significant eye discomfort despite its conspicuous appearance.
But eye redness also can be a sign of other types of potentially serious eye conditions. Particularly if you have eye discharge, you should visit your optician for an eye exam to rule out an infection caused by bacteria, virus or other microorganism.
You should seek immediate care from an eye care professional whenever you experience unusual and persistent redness of the eye accompanied by a sudden change in vision, pain or strong light sensitivity. This type of eye redness can be a sign of other eye problems.
What Causes Subconjunctival Haemorrhages?
Blood in the eye from a subconjunctival haemorrhage usually disappears within a week or two.
Although it is not always possible to identify the source of the problem, some potential causes of subconjunctival haemorrhage include:
Eye trauma (scratch from dust)
A sudden increase in blood pressure that can result from heavy lifting, coughing, sneezing, laughing and constipation
Blood thinners such as aspirin (acetylsalicylic acid) and warfarin
Rarely, a blood clotting disorder or vitamin K deficiency (vitamin K aids the functioning of proteins necessary for blood clotting)
Eye surgery, including LASIK and cataract surgery
How Are Subconjunctival Haemorrhages Treated?
Lubricant artificial tears can soothe the eyes, although eye drops cannot help repair the broken blood vessels.
If you are taking aspirin or blood thinners, continue taking them unless your doctor specifically instructs you to do otherwise.
Make sure not to rub your eye, which can increase the risk of re-bleeding right after onset — similar to how a nose bleed is susceptible to re-bleeding in the early stages.
How Long Do Subconjunctival Haemorrhages Last?
In most cases, it takes seven to 10 days for the haemorrhage to dissipate on its own. As the haemorrhage disappears with time, the affected area can change colour, like a bruise.