Red Eyes - Definitive Guide

A red eye occurs when tiny blood vessels beneath the surface of the eye become inflamed making the eyes appear red and bloodshot. It can affect one or both eyes and is usually caused by something irritating the eye. 

 In most cases, a red eye is not a sign of anything serious and clears up on its own once the irritation is removed. It does not usually cause permanent damage to your eye. 

In some cases, red eyes can be a sign of something more serious and may need treatment. 

Make an appointment with a doctor if you have a red eye, because a history and examination is needed to diagnose the cause, and subsequent treatment.

Make an urgent appointment with a doctor or call 111 if:

• you have a baby under a month old with a red eye
• you have a red eye and wear contact lenses
• your eye is red and painful
• you see rings (haloes) above lights
• you have joint swelling
• you are generally unwell or have a fever

Call an ambulance or go straight to A&E if: 

• you have a severe headache and feel sick
• it hurts to look at the light
• you have changes to your vision such as blurred vision, flashing lights, or wavy lines
• you have loss of vision
• you have injured or pierced your eye
• you have something stuck in your eye
• your eyes are dark red
• you have one pupil bigger than the other

There are many causes of red eye including: 

• Allergies — occur when a substance such as pollen, pet dander, or mould triggers the release of histamine in the body causing an allergic reaction. Symptoms often include redness, itchiness, and watering in both eyes. 
• Dry eye —a condition where the eyes do not produce enough tears. Tears are important to lubricate the eye and keep it comfortable. Dry eye symptoms include pain, redness, stinging and burning. 
• Blepharitis— a common condition where the eyelid becomes red, swollen, and inflamed. Other symptoms may include itching, burning and watering.
• Conjunctivitis — is inflammation of the conjunctiva (the membrane that surrounds the eyeball). It may be caused by an infection or allergy and causes symptoms such as red or pink eyes, swelling, pain, and a sticky or watery discharge. 
• Eye injury —if you injure your eye, the blood vessels in your eye dilate (open) to increase blood supply to the injured area and promote healing. This makes your eye appear red. Eye injuries include puncture wounds, chemical burns, and scratches to the surface of the eye (corneal abrasions). Eye injuries need urgent treatment, so go straight to A&E if you injure your eye. 
• Glaucoma —occurs when fluid builds up at the front of the eye causing increased pressure inside the eye. Glaucoma can occur suddenly, a condition known as angle-closure glaucoma. Symptoms include pain, bright red eyes, seeing rings around lights, loss of vision, nausea, and vomiting. Acute glaucoma is a sight-threatening medical emergency and needs a review at A&E or your local eye hospital. 
• Drinking too much alcohol —drinking excessive amounts of alcohol causes the blood vessels in the eye to clump together making the eyes appear red and bloodshot 
• Smoking —tobacco smoke is irritating to the eyes and can cause red, dry, itchy eyes
• Using whitening eye drops —these contain chemicals called vasoconstrictors that narrow the blood vessels on the surface of the eye. Though they may temporarily reduce redness in the eye, prolonged use can make them less effective meaning you will need to use more and more of the drops to get the same effect. 

Treatment for red eyes depends on the cause. If your red eyes are severe, accompanied by other symptoms, or don’t get better after a few days, make an appointment with a doctor. 

Some at-home treatments for red eye include: 

• avoiding contact with whatever is irritating your eyes
• avoiding touching or rubbing your eyes 
• washing your hands frequently 
• not wearing eye makeup or contact lenses until your symptoms have resolved

• applying cool compresses to your eyes
• rinsing your eyes with cooled, boiled water
• limiting your screen time —the blue light emitted by computers and phone screens can irritate the eye
• using over-the-counter medications. Your pharmacist will recommend a treatment for you based on your symptoms.

An online doctor can help with red eye by asking about your symptoms and examining your eyes. They can make a diagnosis based on your symptoms, advise you on self-care, prescribe a suitable treatment, and recommend referral if necessary. 

It’s easy to book an appointment with an NHS-trained GP at Medicspot. Simply click the link and select an appointment at a time and day that suits you. Appointments are often available the same day.

Your pharmacist can help with red eye by asking about your symptoms and recommending a suitable over-the-counter treatment. They can also advise you on when to see a GP. 

Find a pharmacy near you

A red eye is a common symptom that usually occurs when your eyes are irritated and inflamed. Most cases of red eyes can be treated at home or with over-the-counter medications, but it can also be a sign of something serious. If you have a red eye talk to a doctor and make an appointment today.

Cleveland Clinic: Red Eye January 22nd 2018 (Accessed November 18th 2022) 

NHS: Red eye  March 21st 2022 (Accessed November 18th 2022) 

PubMed: Red Eye: A Guide for Non-specialists April 28th 2017 (Accessed November 18th 2022) 

American Family Physician: Diagnosis and management of Red Eye in Primary Care  January 15th 2010  (Accessed November 18th 2022)