What is red eye?
Red eye is the result of changes in the blood vessels in your eye that make your eye look red or bloodshot; it may occur in one or both eyes. Red eye is usually caused by irritation, infection or trauma. Even everyday causes, such as coughing, sneezing, crying, and lack of sleep, can lead to redness in your eye. Red eye is often accompanied by other eye symptoms, including burning, itching, soreness, tearing and discharge.
Physical irritation leading to red eye can be caused by 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. Prolonged wear of contact lenses also causes irritation that produces red eye. Allergies are a very common cause of red eye, whether they are local, such as an allergic reaction to eye makeup, or more generalized, such as hay fever.
Infections and other inflammations may cause redness resulting from blepharitis (inflammation of the eyelid margin) or conjunctivitis (inflammation of the eye surface). Uveitis and iritis, which are inflammations of structures within the eye, are serious, though less common, causes of red eye. Another serious cause of red eye is acute angle-closure glaucoma. A harmless, but sometimes dramatic, dense area of redness in the white of the eye is usually a subconjunctival hemorrhage, caused by breakage of small, superficial blood vessels.
The goal of the 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 health care provider if you have any eye symptoms that cause you concern.
Seek immediate medical care (call 911) if you have red eye along with serious symptoms such as sudden changes in your vision, severe pain in your eye, high fever (higher than 101 degrees Fahrenheit), if your red eye was caused by either blunt or penetrating trauma, or if you experience sudden swelling of the face, lips or tongue.
Seek prompt medical care if your symptom of red eye is persistent, recurrent, or causes you concern.
What other symptoms might occur with red eye?
Depending on the cause of your red eye, other parts of your body may also be affected. A variety of symptoms commonly occur along with red eye.
Common symptoms that may occur along with red eye
Red eye may accompany other common symptoms including:
- Bleeding or bruising
- Bulging of the eyeball
- Burning feeling in the eyes
- Discharge from the eyes
- Droopy eyeli
- Dry eye
- Gritty feeling
- Inability to turn the eyeball
- Increased tear production
- Runny nose (nasal congestion)
- Sense of a foreign body in the eye
- Sensitivity to light
- Swelling or warmth
Serious symptoms that might indicate a life-threatening condition
Although red eye is usually harmless, it may occur with other symptoms that might indicate a life-threatening condition that should be immediately evaluated in an emergency setting. Seek immediate medical care (call 911) if you, or someone you are with, have red eye along with other life-threatening symptoms including:
Abnormal pupil size or nonreactivity to light
Blunt force trauma to the eye or bones around the eye
High fever (higher than 101 degrees Fahrenheit)
Penetrating eye trauma in which a projectile or sharp object enters the eye
Sudden swelling of the face, lips or tongue
What causes red eye?
In general, anything that irritates or inflames the white part of your eye can cause red eye. The redness you see is usually caused by an increase in the size of small vessels in your eye, which allows more blood into the 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 the breakage of small, superficial 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.
Common causes of red eye
Red eye symptoms may be caused by several common conditions including:
Blepharitis (inflammation of the eyelid margin)
Common cold (viral respiratory infection)
Conjunctivitis (inflammation of the eye surface)
Hay fever or allergic reaction from animal dander, dust, cosmetics or pollen
Irritation from chemicals, environmental factors, or contact lenses
Lack of sleep
Local allergic reactions to makeup or personal care products (contact dermatitis)
Medicamentosa (eye develops sensitivity to eyedrops after long-term use)
Stye or hordeolum (localized bacterial infection of an oil gland or eyelash follicle in the eyelid margin)
Serious causes of red eye
Red eye can also be caused by more serious conditions including:
Acute glaucoma (sudden increase of pressure in the eye)
Endophthalmitis (infection inside the eyeball)
Orbital cellulitis (invasive infection of the soft tissues around the eye)
Periorbital cellulitis (infection of the eyelids or other soft tissue around the eyes)
Uveitis and iritis (inflammation of structures of the eye)
Questions for diagnosing the cause of red eye
To diagnose your condition, your doctor or licensed health care practitioner will ask you several questions related to your red eye including:
When did you first notice your red eye?
Are you taking any medications?
Do you have any allergies?
Has anything hit you in the eye or flown into your eye?
Have you been around anyone with an eye infection recently?
Have you had a similar condition before?
Have you had recent eye surgery?
Do you have red eye in one or both of your eyes?
What other symptoms do you have?
What are the potential complications of red eye?
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. Once the underlying cause is diagnosed, it is important for you to follow the treatment plan that you and your health care professional design specifically for you 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