Eye Health Central

What causes bloodshot eyes?

Why are my eyes red and bloodshot?

Bloodshot eye

Bloodshot eyes or red eyes are usually caused by an insufficient amount of oxygen reaching the cornea and can be a result of eye fatigue, allergies, over wearing contact lenses or airborne pollutants and normally pose little cause for concern, however, if a bloodshot eye is accompanied by pain or impaired vision then this may indicate a more serious eye condition and you may need to seek medical attention. If you have any of the following symptoms: pain in the eye, changes to your sight, it hurts to look at light, severe headache and nausea, you have injured your eye or 1 pupil is bigger than the other then you should go immediately to the A&E

What Causes Bloodshot Eyes?

There are numerous causes and conditions that can cause bloodshot eyes, from lack of sleep to eye infections, they can be broken down into three main categories Environmental, Common eye conditions and Serious eye conditions:

Environmental causes of bloodshot eyes
  • Air Pollution
  • Airborne allergens
  • Smoke - secondhand cigarette smoke, fire-related
  • Dust Particles
  • Dry Air - Air conditioning, airplane travel, arid climates
  • Chemicals - swimming pool chlorine, suntan cream, shampoo etc
  • Fumes - solvents etc

Common eye conditions that can cause bloodshot eyes

Serious eye conditions that can cause bloodshot eyes

We could probably add lifestyle choices in here, as tobacco smoke, marijuana smoke, excess alcohol, lack of sleep and extended periods of screen activity can cause red bloodshot eyes to some degree, fortunately these are non-harmful and usually short-lived and easy to remedy.

How To Get Rid Of Bloodshot Eyes

To relieve bloodshot eyes if helps to first work out the cause, if your eyes are bloodshot due to environmental causes or lifestyle choices such as: allergens, air pollution, smoke, tired eyes etc then a home remedy can be very effective try one or more of the following:

Tea bags

It’s no secret that people find applying a cold tea bag to the eyes soothing. Simply place a cooled tea bag onto your closed eyelids and relax for up to 20 minutes. Any old tea will do but we find green tea, camomile, calendula and fennel tea the most effective. It is thought that these teas help relieve symptoms of bloodshot and red eyes by removing excess fluid that is draining from your eye and relieving swelling and irritation.


Lay flat and place one slice of cucumber on each of your closed eyes, either flip the slice or use a new slice if the cucumber becomes warm.
The soothing and cooling properties of cucumbers are thought to reduce irritation and tired eyes.


Place 2 spoons into iced water to cool, once cooled (not frozen) remove from the glass and place two more spoons into the water (these will begin to cool whilst you are relaxing) Place the concave side of a spoon onto each of your closed eyelids, once the spoons become warm swap with the cooling spoons, repeat this process for up to 20 minutes.
The cooling of the eyes will help constrict blood vessels which should lead to a decrease in red eyes.

Remove contact lenses

If you are a contact lens wearer suffering from bloodshot eyes we recommend you remove your contact lenses and give your eyes a rest. 
Even if your contact lenses are not the cause of your bloodshot eyes then removing them and allowing more oxygen to the surface of the eye will have other benefits, like allowing you to use cold compresses, apply cucumbers or add eye drops if needed.
If using monthly lenses, make sure you give your lenses and your lens case a good clean before reinserting.

Screen-free time

You probably don’t want to hear this, but if you think overuse of screen time has caused your red eyes then give your eyes a rest from your PC, laptop or eye phone, and don’t rush to turn on the TV. A short break relaxing and resting the eyes will help your blinking response return to normal and hence help clean and oxygenate the eye.


A common cause of bloodshot eyes is not enough sleep, particularly if it follows a night of drinking.
Try drinking plenty of water and then catch up on your sleep, you’ll find a good night's sleep will work wonders. 

How To Avoid Red Bloodshot Eyes

There are some things you can do proactively to avoid bloodshot eyes

  • Do not overwear your contact lenses
  • Do not sleep in contact lenses
  • Avoid situations known to cause bloodshot eyes if possible- i.e smoky, dry environments, excessive screen time, 
  • Get a good night's sleep
  • Avoid rubbing your eyes
  • Be proactive in taking antihistamines

Do I Need To See A Doctor For Bloodshot Eyes?

Depending on the severity and the cause of your bloodshot eye(s) you may be able to treat yourself with a home remedy or speak to your pharmacist about what's available over the counter, however if your bloodshot or red eyes are accompanied by 

  • Pain, 
  • Discharge/sticky eyes,
  • Headache 
  • Blurred vision or you 
  • Feeling nauseous 
  • Have a fever 

Then contact your eye care professional or, GP immediately.

The NHS has a great quick guide to help you decide, whether your red eye needs treatment, who to contact and how soon you need to be seen. 

It is always advisable to seek medical advice from a doctor or optician if your bloodshot eyes last more than a couple of days, as they can determine if there is an underlying cause that may need treatment. 

Author: John Dreyer Optometrist Bsc(Hons), MCOPTOM, DipCLP
Created: 15 Aug 2020, Last modified: 20 May 2024