Red Eyes

Medically Reviewed By William C. Lloyd III, MD, FACS

What are red eyes?

Red or bloodshot eyes describe a condition in which the whites of the eyes appear red. Red eyes occur when the blood vessels in the transparent, moist conjunctiva dilate or swell. A variety of mild to serious diseases, disorders and conditions can irritate the conjunctival blood vessels and cause bloodshot eyes.

Common red eye causes include irritation, infection or trauma. Even everyday causes, such as coughing, sneezing, crying, dehydration and lack of sleep, can lead to redness in your eye. Red eyes from contacts or overuse of contacts are also possible.

Other physical irritants leading to red eyes include smoke, smog or dust in the air or by household cleaning products or personal care products, such as shampoo or soap that get in your eyes. In some cases, a bloodshot or red eye or eyes can indicate an emergent condition that can lead to loss of sight, such as acute glaucoma or an eye injury.

Red eyes can occur with other eye symptoms, including burning, itching, soreness, tearing and discharge. Red eyes can begin suddenly and disappear quickly, such as when you have a mild allergic reaction to animal dander or dust. Bloodshot eyes can also develop with time and occur along with additional symptoms, which may be a sign of a more serious condition, such as a corneal ulcer or eye infection.

The goal of medical evaluation is to identify the root cause for red eye. Most red eye is a result of a mild condition and usually resolves on its own. In rare cases, red eye may be a symptom of serious conditions that can threaten your vision and your health. Because your eyes and vision are vital to your quality of life, be sure to see your healthcare provider if you have any eye symptoms that cause you concern. Depending on the underlying cause, treatment for red eyes can range from rest and hydration to more extensive treatment, such as medication or surgery.

Because bloodshot eyes may be a sign of a serious condition, contact your healthcare provider about your symptoms. Seek prompt medical care if you have unexplained, persistent, or severely bloodshot eyes or if you are concerned about your symptoms. Seek immediate medical care (call 911) if you have bloodshot eyes accompanied by severe eye pain, loss of vision, or signs of anaphylactic shock (swollen tongue and throat, hives, and difficulty breathing).

What other symptoms might occur with red eyes?

Red eyes may occur with other symptoms, which vary depending on the underlying disease, disorder or condition. For example, bloodshot eyes due to dry eyes may be accompanied by irritation or eye pain. Bloodshot eyes caused by infection may include eye discharge, swelling, pain, and red eyelids. If you have other symptoms along with your eye symptoms, be sure to tell your healthcare provider. This information will help your doctor diagnose the reason for your eye symptoms.

Vision and other eye-related symptoms that may occur along with red eyes

Bloodshot eyes may accompany vision problems and other eye symptoms including:

  • Bleeding from the eye

  • Discharge from the eye

  • Drooping eyelid

  • Dry or burning eyes 

  • Eye pain

  • Eyelid swelling or warmth

  • Gritty feeling or sensation that something is in the eye

  • Increased sensitivity to light

  • Increased tear production (watery eyes)

  • Itchy eyes

  • Protruding or bulging eye(s) (proptosis)

  • Skin sores or pus-filled bumps on the eyelid

Allergy-related symptoms that may occur along with red eyes

Food allergies, respiratory allergies, insect bite allergies, and skin allergies can produce a variety of symptoms that may include:

Other symptoms that may occur along with red eyes

Bloodshot eyes may accompany other abnormal symptoms including:

Symptoms that might indicate a serious or life-threatening condition

In some cases, red eyes can indicate a serious or life-threatening condition, such as anaphylaxis, which should be immediately evaluated in an emergency setting.

Seek immediate medical care (call 911) for red eyes with any of the following symptoms:

  • Abnormal pupil size or pupil that does not react to light

  • Gaze limitation or eye movement paralysis

  • Itching in the throat or mouth with hives

  • Penetrating eye trauma or blunt force trauma to the eye or bones surrounding the eye

  • Severe headache

  • Severe wheezing or severe difficulty breathing

  • Sudden change in vision, loss of vision, blurred vision, or other sudden vision disturbances

  • Sudden eyelid droop

  • Sudden eye pain

  • Sudden swelling of the face, mouth, tongue or lips

What causes red eyes?

In general, anything that irritates or inflames the white part of your eye can cause red eye. The redness you see is usually due to an increase in the size of small blood vessels in the moist conjunctiva which covers the eyeball. This allows more blood to obscure the underlying white portion of your eye, making it appear red.

Sometimes a bright red patch, called a subconjunctival hemorrhage, appears in the white of your eye as a result of a hemorrhage involving these small, superficial conjunctival blood vessels.

Physical irritation from chemicals in the environment or the home or from prolonged wearing of contact lenses frequently causes red eye. Allergies, blepharitis (inflammation of the eyelid margin), and conjunctivitis (inflammation of the eye surface) are other very common causes of red eye.

Trauma in the eye area, whether blunt or penetrating, is a more worrisome reason for red eye. Acute angle-closure glaucoma (sudden increase of the pressure in your eye) as well as uveitis and iritis (inflammation of structures of the eye) are vision-threatening causes of red eye, but fortunately, they are not common.

Although bloodshot eyes can be caused by relatively mild conditions, such as dry eyes or the common cold, bloodshot eyes can also be caused by serious or life-threatening conditions, such as an anaphylactic reaction or acute glaucoma, both of which should be immediately evaluated in an emergency setting.

Infectious causes of red eyes

Bloodshot eyes can be caused by a variety of infections including:

  • Bacterial or viral conjunctivitis (inflammation of the eye surface)

  • Blepharitis (infected eyelash follicle)

  • Chalazion (inflammation of a blocked oil gland in the eyelid margin)

  • Common cold (viral respiratory infection)

  • Dacryocystitis (infected tear duct)

  • Iritis (inflammation of the iris)

  • Keratitis (inflammation of the cornea)

  • Orbital cellulitis (acute infection of the area surrounding the eye)

  • Scleritis (inflammation of the white of the eye)

  • Sinus infection or sinusitis

  • Stye (also called a hordeolum, which is an infected oil gland)

  • Uveitis (inflammation of the iris, choroid, and ciliary body in the eye)

Allergic causes of red eyes

Bloodshot eyes can be caused by mild to serious allergic reactions including:

  • Anaphylactic allergic reaction to any substance

  • Drug allergy, such as penicillin or codeine

  • Hay fever or allergic reaction from animal dander, dust, or pollen

  • Insect bite allergy, such as bee sting

  • Local allergic reactions to makeup or personal care products (contact dermatitis)

Traumatic and other physical causes of red eyes

Bloodshot eyes can arise from injury and other physical conditions including:

  • Contact lens use

  • Coughing or straining

  • Eye injury or surgery

  • Facial burn or other trauma

  • Foreign object in eye

  • Hyphema (bleeding inside the front of the eye behind the cornea)

  • Scratches on the cornea

  • Subconjunctival hemorrhage (broken blood vessel on the white of the eye)

Other causes of red eyes

Bloodshot eyes can be due to various other diseases, disorders and conditions including:

  • Acute glaucoma

  • Autoimmune diseases

  • Blocked tear duct

  • Corneal ulcer

  • Crying

  • Dehydration

  • Dry eyes

  • Ectropion (turned-out eyelid)

  • Entropion (turned-in eyelid)

  • Eye fatigue

  • Keratoconus (cone-like cornea)

  • Lack of sleep

  • Pinguecula (yellowish, benign growth on the conjunctiva near the cornea)

  • Pterygium (fleshy, benign growth on the sclera that may extend onto the cornea)

When should you see a doctor for red eyes?

When your eyes are red, it is usually not serious and the problem resolves on its own. However, there are times when seeing a healthcare provider is the safest option to determine the extent of the injury or diagnose more serious causes.

See a doctor promptly when:

  • Red or bloodshot eyes persist for more than a couple of days.

  • There is something in your eye that will not come out.

  • You are having vision problems or your vision is changing.

  • Your eyes have a thick discharge or crusting, especially if it is brown, green or yellow.

  • You recently had eye surgery or an eye injection.

  • You take blood thinners, such as warfarin (Coumadin).

  • Your eyes are sensitive to light or are painful.

Call 911 or go to your nearest emergency room for red eyes when:

  • Chemicals, cleaners, or other substances have splashed into your eye.

  • You cannot open your eye(s) or keep your eye(s) open.

  • You have any kind of trauma to the eye, including penetrating trauma to the eye itself and blunt trauma to the eye or surrounding bones.

  • You have a fever, confusion, severe headache, severe eye pain, or extreme light sensitivity.

  • You have nausea and vomiting.

  • You have sudden vision changes, including blurred vision or seeing halos around lights.

How do doctors diagnose the cause of red eyes?

To diagnose the underlying cause of red eyes or bloodshot eyes, your doctor will take a medical history, perform an exam, and possibly order testing. Questions your doctor may ask about your eyes include:

  • When did your symptoms start? Does the redness come and go or is it constant?

  • Have you had any change in your vision or visual disturbances?

  • Did you eat any foods or come in contact with any unusual substances preceding the onset of your symptoms?

  • Did you injure your eye or have eye surgery recently?

  • Do you have any eye pain, burning, itchiness or discharge? Does it hurt to move your eyes?

  • Do you have symptoms in one eye or both eyes?

  • Do you wear contacts?

  • Do you have other symptoms, such as headache or nausea?

  • What medications and dietary supplements do you take?

  • What medical conditions do you have?

Your doctor will perform a physical exam, which may include a complete eye exam and a vision test. Additional testing may be necessary including:

  • Blood tests to look for certain antibodies that are present in autoimmune diseases

  • Culture of eye discharge to find bacterial causes 

  • Tear osmolarity to test for dry eye

  • Tear turnover and evaporation rate

It is not always possible to diagnose an underlying cause or condition. If the bloodshot eyes persist and your provider is unable to determine a cause, seeking a second opinion may give you more information and answers.

How do you treat red eyes?

Treatment for red or bloodshot eyes may or may not be necessary. Redness due to fatigue, lack of sleep, eye strain, crying, and other everyday causes usually responds to rest. When a medical condition is causing eye redness, treatment will depend on the specific cause. Your doctor may prescribe any of the following:

  • Antibiotic or antiviral eye drops

  • Antihistamines as either eye drops or in an oral dosage form along with other allergy medicines or eye drops

  • Artificial tears and other dry eye treatments, such as cyclosporine (Restasis)

  • Corticosteroid eye drops to reduce inflammation

  • Glaucoma treatment in the form of eye drops

  • NSAID (nonsteroidal anti-inflammatory drug) eye drops to ease pain and reduce inflammation

  • Oral antibiotic therapy

For eye injuries, doctors may recommend eye patches and other strategies to promote healing. Eye surgery may be necessary in rare cases.

What are some home remedies for red eyes?

Here is a list of what helps red eyes that you can do at home:

  • Apply compresses. Cool compresses are generally better for relieving irritation. But warm compresses sometimes feel more soothing and can help remove eye crust.

  • Avoid allergic and irritant triggers, such as animal dander, pollen, and chemical fumes.

  • Change sheets and towels frequently.

  • Take a break from contact lenses.

  • Use over-the-counter (OTC) artificial tears and other eye lubricants. For frequent use, buy the preservative-free form.

  • Use OTC antihistamine eye drops to treat seasonal allergies.

  • Use decongestant eye drops for short-term—three days or less—relief of redness. Using these products for longer than the recommended time can result in rebound redness.

  • Wash your hands often and avoid touching or rubbing your eyes.

What are the potential complications of red eyes?

Red eye is usually the result of mild conditions that do not cause permanent damage to the eye. In rare cases, red eye is caused by a serious condition, including glaucoma or trauma, that, left untreated, can lead to permanent damage to the eye.

Complications from underlying causes of bloodshot eyes can be progressive. It is important to contact your healthcare provider when you have bloodshot eyes or other unusual symptoms that persist or become worse with time.

Once the underlying cause is diagnosed, it is important to follow your treatment plan to reduce the risk of potential complications including:

  • Chronic eye pain or discomfort

  • Loss of the eye and orbit (bone surrounding the eye)

  • Loss of vision and blindness

  • Scarring of the eye

  • Spread of infection
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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Sep 3
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