Help and frequently asked questions

What can cause bloodshot eyes?


Bloodshot eyes are a fairly common occurrence, and despite looking quite alarming, they rarely signal a serious condition. This is particularly true if your eye is red, but not painful. There could be a more serious underlying cause if you are also suffering eye pain, especially if this is accompanied by other symptoms such as light sensitivity, headaches and blurry vision.Here are some of the most common causes of bloodshot eyes, as well as potential treatments. However, you should always check with an optometrist to confirm a diagnosis.

Conjunctivitis known as pink eye in the US, conjunctivitis is arguably the biggest cause of bloodshot eyes. The conjunctiva is a thin layer of tissue that covers the eyeball and the inner surfaces of your eyelids - and conjunctivitis is when this tissue becomes inflamed. There are three main causes of conjunctivitis: allergies, irritants and infections. These lead to the blood vessels in the eye swelling and making it appear red and sometimes feel gritty. The symptoms of conjunctivitis will tend to vary slightly depending on the cause, with allergens usually affecting both eyes and being extremely itchy. Infections may accompany a cold and can also create a discharge from the eye. Most of the time, conjunctivitis will clear up on its own - but you may be prescribed eye drops if it is particularly persistent.

You should also avoid wearing eye make-up or contact lenses until it clears up.Thorough eye hygiene, including compression with a clean, damp cloth can help. However, conjunctivitis can be very contagious, so make sure not to share towels or pillows with anyone.

Burst blood vessel

A burst blood vessel in the eye is another common reason for developing bloodshot eyes. The medical name for this is a subconjunctival haemorrhage and it can be caused by straining, coughing, vomiting or even heavy sneezing.Burst blood vessels can appear very alarming because they are bright red and can cover large portions of the eye. However, no treatment is usually required and the haemorrhage should fade within a couple of weeks. Like most bruises, burst blood vessels may go a yellow-green colour before disappearing, but this is normal and shouldn't be a cause for concern. If your eye does not clear up after two weeks or you regularly suffer from burst blood vessels in your eye, it is worth visiting an optometrist.

My eye is bloodshot and painful, what could it be?

Bloodshot eyes, when accompanied by pain or significant discomfort, could be a sign of more serious conditions. Here are some potential reasons for painful, red eyes:

  • Acute glaucoma is when there is a sudden build-up of pressure inside the eye. This can put pressure on vital structures in the eye, leading to serious vision problems and even blindness.
  • Corneal ulcers are typically caused by infections and may also make you sensitive to light. They are more common in contact lens wearers and are also linked to the herpes simplex virus. Iritis is a condition where the iris - the coloured part of the eye - becomes inflamed. There are a number of causes, and you may experience blurred vision and headaches.
  • A scratch to the cornea or a particle in your eye could lead to it becoming bloodshot. Once a foreign body is removed, you may be given antibiotic eye drops and ointment to prevent an infection occurring during the healing process.