Red eyes can be a serious warning sign, but they are usually a sign of a mild eye condition, such as conjunctivitis or a broken blood vessel in the eye. If your red eyes are painful, there may be a more serious problem.
If your red eyes don't improve after a few days, be sure to see your doctor. But if you experience any of the following, call your doctor or go to the nearest emergency room immediately:
Red eyes with pain
Have other symptoms such as decreased vision, sensitivity to light, severe headache, or feeling sick
Have a recent eye injury, especially if the eye was injured by a sharp object.
In this article, we aim to familiarize you with the symptoms that may cause red eyes. However, it is emphasized that this information is not a guide for diagnosis and self-treatment; be sure to see a doctor to determine the cause of the disease and appropriate treatment.
The most common causes of painless red eyes
The most common causes of painless red eyes are minor problems, such as conjunctivitis or ruptured blood vessels in the eye. These problems do not affect vision and usually resolve on their own after a week or two.
Conjunctivitis
Conjunctivitis is an inflammation (swelling and irritation) of the conjunctiva (the thin layer of tissue that covers the eyeball and the inner surface of the eyelids).
Conjunctivitis causes the blood vessels in the eye to swell, making one or both eyes red and bloodshot, and the patient may feel like there is grit in the eye.
Itchy and watery eyes, and a sticky substance on the eyelashes can be other symptoms of conjunctivitis.
Conjunctivitis can be caused by an infection, an allergy (for example, an allergy to pollen), or an allergen such as chlorine or dust.
Treatment depends entirely on the cause of the condition. Sometimes, no intervention is needed because the inflammation resolves on its own.
Your doctor may recommend the following:
Clean the discharge around or inside the eye regularly.
Do not wear any type of contact lenses until the inflammation has completely healed.
Wash your hands frequently with soap and water, and if the eye is infected, do not share pillows or towels with others until the condition has completely healed.
Use antibiotic eye drops for infections and medications such as antihistamines for allergies, as prescribed by your doctor.
Broken blood vessels in the eye
Sometimes, straining, coughing, or trauma to the eye can cause a superficial blood vessel in the eye to break, causing a red, bloody spot in the eye called a subconjunctival hemorrhage.
If you are taking medications such as aspirin or warfarin, this condition will be a serious warning for you (because these drugs reduce the ability of the blood to clot, and therefore the amount of redness in the eye becomes much greater); but usually this condition is not very serious and resolves on its own after a few weeks.
The most common causes of red eyes with pain
If you have red eyes with pain or other symptoms such as decreased vision, it may be due to one of the following diseases; note that these diseases can sometimes be very serious and threaten your vision. Therefore, you should see a doctor as soon as possible.
Uveitis
Inflammation of the iris (inflammation of the colored part of the eye) is usually known as anterior uveitis.
In this condition, as well as red eyes, you may notice that your eyes are sensitive to light; blurred vision; and have a headache.
Often, no specific cause is found, but sometimes uveitis can be caused by a serious problem with the immune system or an infection.
Uveitis usually responds quickly to treatment with steroid medications, which reduce inflammation. It rarely causes serious problems.
Acute glaucoma
Acute glaucoma is a serious and dangerous condition caused by a sudden increase in pressure inside the eye. Your eye may become very red and painful, and you may feel sick and see halos around lights. Your vision may also become blurry and hazy.
If your doctor thinks you may have acute glaucoma, he or she will refer you to an eye specialist right away, because if the condition is not treated quickly, it can lead to complete vision loss.
Corneal ulcer (sore on the cornea)
A sore on the cornea (the outermost layer at the front of the eye) is usually caused by a bacterial or viral infection. This condition can cause redness of the eye, sensitivity to light, and a foreign body sensation in the eye.
A corneal ulcer caused by a bacterial infection is most common in people who wear contact lenses, while a viral corneal ulcer is most common in people who have recurrent cold sores.
If your doctor thinks you have a corneal ulcer, he or she will refer you to an eye specialist for treatment.
A scratch on the cornea or a foreign body sensation in the eye
Sometimes, a red, painful eye can be caused by a foreign object, such as a grain of sand, getting into your eye.
If something is in your eye, a hospital emergency room doctor will remove it. To do this, before starting, local anesthetic drops are placed in the eye to reduce pain and numb the eye.
If a foreign object has scratched the surface of the eye, the eye will be numbed when the drops are applied.
Your eye will be drained, and you will feel some pain. After the object is removed, your doctor will prescribe antibiotic drops or ointment for you to use for a few days. This will reduce the chance of infection while your eye heals.