Bloodshot eye

A bloodshot eye can result from irritation to the surface of the eye or bleeding from the tiny blood vessels in the eye. It can appear as visible red veins in the eyes, overall redness or a spot of blood on the white of the eyes. A bloodshot eye is also known as red eye.

There are many common causes of bloodshot eyes, including allergies, trauma and infection and inflammation. A bloodshot eye may be nothing to worry about, but red eyes accompanied by pain or vision problems could indicate a more serious condition. Always see your eye doctor or GP if you’re worried.

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Bloodshot eye causes

There are several possible causes of a red eye. An overall red eye that gets gradually worse is often due to an eye infection or allergy. If you wake up with a bloodshot eye, you may have a subconjunctival haemorrhage, a small visible (intensely red) bleed that usually clears up within 5 – 10 days (Source: The College of Optometrists). However, see your doctor or optometrist if your eyes are bloodshot and you experience any vision changes or pain.

Common bloodshot eye causes include:

An infection of the conjunctiva on the surface of the eye is called conjunctivitis (also known as pink eye). Conjunctivitis is the most common cause of a red eye (Source: American Family Physician) and can result from a bacterial or viral infection. Good eye care and keeping the eyes clean can help avoid or treat minor eye infections.
Acute glaucoma (narrow-angle glaucoma) is one of the possible causes of a red eye. If you experience a sudden bloodshot eye, a severe headache, intense eye pain, seeing halos around lights, eye tenderness, blurred vision, or nausea and vomiting, go to A&E (Source: NHS). Open angle glaucoma typically progresses slowly and is not associated with a red eye.
A corneal abrasion occurs when the front outer surface of the eye, the cornea, is scratched. A corneal abrasion is uncomfortable and can cause a gritty feeling and watery, bloodshot eyes. A scratched cornea is more prone to infection, which can lead to a corneal ulcer, so good eye care is essential while the corneal abrasion heals.

People who take blood-thinning medication, have high blood pressure or diabetes, or are aged between 60 and 80 may be more prone to bloodshot eyes (Source: The College of Optometrists).

Why are my eyes bloodshot?

When the eye’s surface gets irritated, or its tiny blood vessels get damaged, the white of the eyes can develop a bloodshot effect. Sometimes the eye has a general red appearance, often caused by infection or allergies. In other cases, there appears to be a visible bleed from a burst blood vessel in the eye, called a subconjunctival haemorrhage.

Red eye

Red eye is a commonly used term to describe bloodshot eyes, particularly when associated with conjunctivitis. Some of the causes of red eye, like allergies and infection, can also cause redness around your eyes due to skin irritation or soreness. Red eyes often get better on their own, but see your doctor if you experience pain or vision changes along with red eyes.

Bloodshot eye on one side

You may experience a red bloodshot eye on one side only. If you have one bloodshot eye and no pain or vision problems, it will likely get better on its own. To prevent the red eye from worsening, avoid rubbing or touching the eye, and maintain good eye care. If you usually wear contact lenses, consider avoiding them until your red eye improves.

If your eye is bloodshot on one side and you are experiencing pain or blurred vision, or if the redness lasts for more than a few days, see your eye doctor.

Sudden bloodshot eye

A sudden bloodshot eye can be related to increased pressure in the head or eye, causing a tiny blood vessel to burst in the white of the eye. It may happen after coughing, sneezing or vomiting. When a red eye is due to an allergy or infection, the redness tends to increase more slowly over time as the eye becomes more irritated.

How to get rid of bloodshot eyes

Treatment for bloodshot eyes depends upon the cause. Get treatment advice from your doctor or trained healthcare professional if you experience other symptoms alongside a bloodshot eye, like headache, blurred vision or pain, or if it doesn’t get better after a few days (Source: NIdirect.gov).

Possible red eye treatments:

Over-the-counter lubricating eye drops, like artificial tears, to help soothe dry eyes.
Your GP might prescribe antibiotic eye drops for red eyes if they suspect an infection.
Antihistamines to calm down an allergy response.
A warm compress to help soothe irritated eyes at home.

Bloodshot eyes and headache

Bloodshot eyes with a headache can indicate a serious health condition, like high blood pressure or an aneurysm, which are medical emergencies.

Headaches and burst blood vessels in the eyes can both be due to high blood pressure (hypertension), which can be dangerous if not brought under control.
A rare but serious condition that may present with headache and red eye is a ruptured cavernous carotid aneurysm (Source: American Journal of Emergency Medicine), which needs urgent medical attention.
Migraines may cause headaches, bloodshot eyes and other symptoms, like light sensitivity. These eye changes are due to irritation of the trigeminal nerve that runs behind the eye and is involved in migraine attacks (Source: Migraine Again). Cluster headaches can also cause red eyes and severe head pain, sweating, and agitation (Source: NHS).

Bloodshot eye after cataract surgery

A bloodshot eye is a common side effect of cataract surgery (Source: American Academy of Ophthalmology). This redness can be due to the eye surgery itself disrupting the eye’s surface, inflammation, or a burst blood vessel (subconjunctival haemorrhage). In some cases, the eye drops used after surgery can cause irritation and red eyes.

Bloodshot eyes should improve within a few days after cataract surgery (Source: RNIB), but if you experience pain, vision changes or light sensitivity alongside bloodshot eyes, seek advice from your ophthalmologist.

Frequently asked questions

A bloodshot eye due to allergy, conjunctivitis or another minor cause should clear up within a few days. A small bleed in the eye (subconjunctival haemorrhage) can take 5-10 days to resolve. Always see your doctor for advice if your bloodshot eye is accompanied by pain or other worrying symptoms, like headaches or vision changes, or if it lasts longer than expected.
Red, itchy eyes are most commonly due to an allergy or infection (conjunctivitis). An allergen, like pet dander or pollen, can irritate the surface of the eye and cause unpleasant symptoms, including redness and itchiness. An eye infection can have similar symptoms as well as crusting, weeping and watering.

Allergies can be treated with antihistamines or soothed with lubricating eye drops. Eye infections often clear up independently with good eye care and regular bathing with clean, warm water. If that doesn’t help, your GP may recommend antibiotic eyedrops.
Yes, COVID-19 can cause bloodshot eyes. We know that coronavirus causes respiratory symptoms, but studies have shown that it also causes ocular symptoms similar to acute conjunctivitis, including red eyes (Source: Clinical Microbiology and Infection). Other common eye symptoms of coronavirus include a burning sensation and watery eyes.

Conclusion

In most cases, bloodshot eyes are nothing to worry about and clear up without intervention. However, if your eye remains red for more than a few days, you have a headache, vision changes or any other worrying symptoms alongside bloodshot eyes, see your eye doctor or GP for advice.

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Medically reviewed by: The Royal College of Ophthalmologists on 28/07/2022

Edited by: Nick Astbury FRCS FRCOphth FRCP
Clinical Associate Professor
LSHTM

The Royal College of Ophthalmologists champions excellence in the practice of ophthalmology and is the only professional membership body for medically qualified ophthalmologists. The RCOphth is unable to offer direct advice to patients. If you’re concerned about the health of your eyes, you should seek medical advice from your GP, optometrist or ophthalmologist.