Other terms for red eye, include "pink eye" and "bloodshot eyes." Irritation, blood in the eye, or inflamed blood vessels can cause the eye to appear red.
Often, the cause is not serious, and home remedies can resolve the problem. Sometimes there is a more serious underlying condition.
An eye with a sharp, aching, or throbbing pain, or a pain that gets worse in response to light, needs urgent medical help.
Other reasons to see a doctor are if eyesight changes or there are other symptoms. Symptoms to look out for include headache, sensitivity to light, feeling sick, or vomiting.
What is red eye?
Suitable eye drops can often help solve the problem of red or pink eyes.
Red eye usually means that the whites of the eyes appear bloodshot. This happens because of changes to the blood vessels that supply the membrane covering the front of the eye.
The conjunctiva is the membrane that covers the front of the eye and lines the eyelids. The blood vessels of this membrane can dilate, causing the eyes to appear reddened. This is usually caused by:
- infection, for example with bacteria
- allergic reaction
Rarer problems can also cause the eye to become red, such as an increase in pressure inside the eye.
In most cases, the cause is conjunctivitis.
Depending on the cause, red eye can often be treated at home.
Here are some tips.
- Regularly place a cool compress over the eyes, made by soaking clean cotton wool or cloth in warm or cold water and then squeezing it out.
- Avoid eye makeup, or choose hypoallergenic eye make up.
- Use artificial tears, which are available for purchase online or over-the-counter or from pharmacies.
- Apply antihistamine drops if red eyes are due, for example to a seasonal allergy. These are also available for purchase online.
If you are planning to use eye drops, speak to a health care provider first, as some drops may increase redness.
To prevent red eyes from starting or worsening:
- Avoid smoke, pollen, dust, and other triggers.
- Do not wear contact lenses until the red eye clears.
- Always clean lenses properly and do not reuse disposable lenses.
- Wash your hands regularly and avoid touching the eyes, to prevent infection.
- Wash clothes, pillowcases, and towels regularly.
- Bathe or shower before bed or after coming in from outside if you have a seasonal allergy.
- Wear sunglasses to protect the eyes from pollen or dust when outside.
Conjunctivitis (pink eye)
Conjunctivitis means inflammation of the surface of the eye, and it has several different causes.
Bacterial or viral conjunctivitis: There is often a discharge. This discharge will often be stickier in cases involving bacteria. It can be relieved by wiping closed eyelids with water or a compress. Never use the same compress on both eyes.
If the symptoms are still there after a week, you should see a doctor. If the cause is bacterial, you may need antibiotic eye drops.
Cold or flu: These can be linked to infectious conjunctivitis. This type of red eye usually spreads quickly to affect both eyes.
Allergy: Seasonal allergies can affect the eyes, for example, an allergy to pollen or animals.
Irritation: This can be either:
- physical irritation, perhaps caused by an object in the eye
- chemical, for example, after swimming in a chlorinated pool
Most cases of conjunctivitis clear up without any medical help.
A doctor may prescribe antibacterial eye drops, but these will not help if the cause is viral.
Allergies can improve with drugs. Some antihistamine tablets and eye drops for allergies do not need a doctor's prescription.
Other causes and treatments
Other common conditions may cause red eyes. The surface of the eye is not always reddened, but the wider eye area may appear red.
Symptoms include itching, redness, flaking, and crusting on the edge of the eyelids. This is a common form of inflammation that can stem from bacteria or problems with glands under the eyelids.
It may need medical attention to prevent complications.
A warm compress can be applied three to four times a day for a week. This will help unblock the pores in the eyelid.
This is a bump that tends to occur further back from the edge of the eyelid than a stye. It is not caused by bacteria but by a gland in the eyelid becoming blocked.
Treatments and home care are similar to those for conjunctivitis, including warm compresses.
A styes or chalazion should not be squeezed. They may go away after home treatment. If they do not go away, they may need medical treatment, such as antibiotic ointment or a steroid injection.
An eye specialist may surgically remove large bumps that do not heal or that obstruct vision.
This refers to a broken blood vessel immediately beneath the surface of the eye. It is a harmless condition that usually goes away within a week or two.
Dry eyes and rubbing the eyes can cause them to go red.
These can lead to red eye. This is a common problem resulting from the eyes producing fewer tears, or greater loss of the watery substance from the eye. Artificial tears may help.
If the dry eyes are associated with the work environment or using computer screens, changes may also help. Using protective glasses in a dusty environment or taking breaks from screen work are examples.
These may cause red eye when worn for long periods. Wearers can cut down the amount of time they are left in to avoid the problem. Using artificial tears may also help.
If a chemical has splashed into the eye or if you touch your eye after handling chili peppers, rinse it immediately with water.
If red eye is accompanied by bruising around the eye following a trauma, apply an ice pack for 15 to 20 minutes at a time, every hour for the first day, to reduce swelling.
If vision is affected or if there is blood in the eye or pain with movement, see a doctor at once.
Irritation or infection can cause redness and inflammation. Artificial tears may relieve discomfort.
A stye is a bump that forms on the eyelid. Never squeeze or pop a stye. They usually go away without treatment.
A subconjunctival hemorrhage is when blood leaks from the blood vessels, causing a bright red patch. It usually goes away without treatment.
A reaction to allergens, such as grass or dust, can cause the eyes to become red or pink. Antihistamine eye drops may help.
Image credit p33tr 2007
Some serious conditions linked to red eye
Less commonly, there may be a more serious underlying problem that needs medical attention.
Corneal scratch or abrasion: Damage to the surface of the eye is not a serious problem itself, but needs medical attention to prevent the damage getting worse, and to prevent infection or ulcers. If there is something in the eye, the doctor may need to remove it.
Uveitis: Inflammation affects the inside of the eye and particularly the part that gives the eye its color. This can impact vision. An eye specialist will prescribe medication.
Glaucoma: This serious condition can damage the optic nerve, resulting in blindness. It is caused by pressure building up inside the eye. Symptoms may not appear until the later stages.
If there are symptoms, they can include redness, vision changes, eye pain, headache, nausea, and vomiting. Glaucoma needs specialist attention.
If symptoms include the following, you should see a doctor:
- a thick discharge
- pain in the eye
- sensitivity to light
- double vision
An underlying cause may need treatment.