Red Eye

Red eyes are one of those things that many people experience from time to time. This can be uncomfortable and you may want to get rid of the bloodshot look as soon as possible. First, you need to figure out what may be causing the normally white part of your eye, the sclera, to appear red.

Such red eyes can be from conditions that vary from conjunctivitis (pink eye) to things such as dry eye or a burst blood vessel.

This article will explore how red eye may correspond to other symptoms, examine various causes, consider treatments and look into other aspects of this common issue.

Closeup of a red eye

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Symptoms of Red Eyes

If you have red eyes, finding out what may be going on can come down to other symptoms that you also notice, which may offer clues as to what's going on.

Conjunctivitis is one possibility. Besides the red color of the whites of your eyes, other symptoms that you might notice include:

  • Discharge
  • Increased tear production
  • Foreign body sensation
  • Crustiness around the lashes
  • Swelling of the protective membrane of the eye, known as the conjunctiva
  • Burning or itching sensation
  • Difficulty wearing contact lenses

A burst blood vessel, otherwise known as a hyphema, where the blood collects between the colored portion of the eye and the clear dome, may also account for redness. Other symptoms to look for are the following:

  • Blood coming from the eye
  • Light sensitivity
  • Pain
  • Vision that's unclear or blocked

Dry eye, which can also redden the surface, is another possibility. Some other dry eye symptoms include:

  • Foreign body sensation
  • Burning or stinging
  • Light sensitivity
  • Blurriness

Eye allergy can also be a common source of red eyes. This may be a prime suspect if you know it's allergy season. Other symptoms to look out for:

  • Itching, which goes hand in hand with eye allergy
  • Mucus discharge (can be watery or white and stringy)
  • Puffy swollen eyelids

Glaucoma cases that come on suddenly may also cause eye redness. Other symptoms associated with what's known as narrow-angle glaucoma include:

  • Severe eye pain
  • Feeling nauseous and/or vomiting
  • Seeing halos around lights
  • Headache
  • Eye tenderness
  • Visual blurriness

Endophthalmitis infection, in which there's swelling within the eyeball due to either bacteria or fungus, is a serious, vision-threatening infection that can cause redness. This may at times occur after cataract surgery (to replace a clouded lens) or other eye surgery. The following are additional symptoms to watch for:

  • Vision decrease
  • Eye pain
  • Eyelid swelling

Causes of Red Eyes

Lots of things may lead to red eyes. Some of the most common underlying causes involve:

  • Infection
  • Allergy
  • Dryness

Redness in the eye can often be linked to the blood vessels. For example, when there's an infection such as conjunctivitis (the tissue covering the eye's surface), the blood vessels in the area become enlarged. As these become more visible, the eye turns red.

Likewise, with allergy, when a substance called histamine is released after exposure to allergens like pollen, the blood vessels swell up. These once again are located on the conjunctiva and become more noticeable.

What Medications Can Cause Red Eyes?

Some eye medications can cause red eyes.

Ironically, what's known as vasoconstrictor drops (such as Visine), meant to whiten eyes by temporarily shrinking blood vessels, can have a rebound effect. The blood vessels may become more dilated than normal as the drugs wear off, and the eyes become redder.

Also, several categories of glaucoma medication, meant to reduce pressure in the eye, can sometimes cause redness. These can include:

  • Beta blocking agents aimed at reducing the amount of fluid produced in the eye may cause redness.
  • Carbonic anhydrase inhibitors, which are also meant to reduce fluid, can induce redness.

How to Treat Red Eyes

It may be possible to treat mild cases of red eyes caused by irritation or passing allergies with home remedies. You may rid yourself of red eyes with the following:

  • Place a cool washcloth on your closed lids once or twice a day.
  • Avoid anything that irritates your eyes and may trigger redness, such as smoke, allergens, pet dander, and chlorine.
  • Apply artificial tears up to four times a day. These can rinse away allergens and soothe irritation.
  • Relieve allergy-related eye itching with over-the-counter antihistamine eye drops.
  • Avoid touching your eyes with your fingers unless you have just washed your hands.

But if symptoms persist for more than a week, this may signal that you have an infection, which needs to be treated by an ophthalmologist.

Are There Tests to Diagnose the Cause of Red Eye?

With red eye it is often necessary to look at what is likely causing these and then test for the various conditions. Here are some tests you may undergo if you have persistent red eyes:

  • If pink eye is suspected, and this has gone on for more than a couple of weeks, an ophthalmologist may swab cells from your eyelid and send these to a laboratory to be cultured. This way, they can determine if the cause of the pink eye is viral or bacterial.
  • To determine if your red eye is related to dryness, a Schirmer test can be done to see if your eyes are producing enough tears. This involves placing a portion of a strip of paper in the lower eyelid and determining how much of the paper is moist.
  • To find out if you have an eye allergy, blood and skin testing can be done to look for a reaction and determine the source of your allergy.
  • To find out if you have narrow-angle glaucoma, the ophthalmologist can do a gonioscopy test to observe the eye's drainage system. Also, to verify that the angle is indeed narrow, an ultrasound can be performed.
  • Diagnosing endophthalmitis requires a complete eye exam, intraocular fluid culturing, and an ultrasound of the eye.

When to See a Healthcare Provider

While red eyes often just need a little extra care, it's important to know when to seek help. Be sure to promptly contact an ophthalmologist for your red eye if:

  • Your eye becomes exceptionally tender or painful.
  • You notice mucus coming from the eye or crusting along the lashes.
  • You experience light sensitivity.
  • You develop a fever.
  • You have known exposure to someone with pink eye.
  • Your red eye doesn't go away on its own after a week of treatment with over-the-counter remedies.


Red eyes can be an extremely common symptom of various conditions ranging from dry eye to allergies and infection. By looking at other symptoms, you may get a clearer picture of what may be causing your eyes to redden.

Many of these conditions can cause blood vessels in the eyes to become enlarged and more noticeable. In mild cases, home remedies such as applying a cool washcloth or rinsing your eyes with artificial tears may suffice. But if symptoms linger or become more serious, you should promptly see an ophthalmologist.

Frequently Asked Questions

  • What causes red eyes?

    Red eyes can be the result of a number of different conditions that cause the blood vessels in the eyes to become enlarged and more visible.

    They can even be caused by vasoconstricting drops meant to reduce the size of blood vessels and whiten eyes. When these are stopped, the blood vessels may enlarge even more than normal, making the eye appear red.

  • How can I get rid of red eyes?

    That depends on the source of the red eye. If you can get to the root, such as allergy, dry eye, or infection, you should undergo treatment for this condition. If eyes are just irritated, home remedies to soothe irritation may suffice.

    If red eyes don't go away with home remedies or become painful, you should promptly check with an ophthalmologist.

  • Can red eyes be associated with COVID-19?

    Yes. In some cases, those with COVID-19 develop pink eye. But just because you have pink eye, does not mean that you have COVID-19. It could be the usual bacterial or viral pink eye or even allergies, which can also have similar symptoms.

16 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention. Conjunctivitis (pink eye).

  2. American Academy of Ophthalmology. What is hyphema?

  3. National Eye Institute. Dry eye.

  4. Johns Hopkins Medicine. Allergic conjunctivitis.

  5. National Health Services. Glaucoma.

  6. Mount Sinai. Endophthalmitis.

  7. University of Michigan Health Kellogg Eye Center. Conjunctivitis (pink eye).

  8. Mount Sinai. Allergic conjunctivitis.

  9. University of Utah. Eye whitening drops: what you need to know.

  10. American Academy of Ophthalmology. Glaucoma eye drops.

  11. American Academy of Ophthalmology. Home remedies for bloodshot eyes.

  12. New York University Langone Health. Diagnosing conjunctivitis.

  13. Mount Sinai. Schirmer test.

  14. Wills Eye Hospital. Angle closure glaucoma FAQS.

  15. University of Michigan Health Kellogg Eye Center. Endophthalmitis.

  16. American Academy of Ophthalmology. Is it COVID-19 or allergies?

By Maxine Lipner
Maxine Lipner is a long-time health and medical writer with over 30 years of experience covering ophthalmology, oncology, and general health and wellness.