What is a red eye?
A “red eye” is a general term that is used to describe red, irritated, and bloodshot eyes. The redness happens when tiny blood vessels under the eye’s surface get larger or become inflamed. Usually, it is a reaction to something that is irritating the eye. The condition can affect one or both eyes, and it can develop over time or appear suddenly, such as with allergies or an eye injury.
Red eyes can be accompanied by eye pain, itching, eye discharge, swollen eyes, or changes in vision, such as blurred vision. Many times, though, a red eye looks worse than it feels. Many cases of red eye are relatively harmless and usually improve with home remedies or over-the-counter treatments.
However, if eyes remain red for more than one week, or if vision is affected, or if there is pain, an appointment with an ophthalmologist (eye doctor), should be made for a medical diagnosis and proper treatment.
What causes red eye?
Red eye has many different causes. Sometimes it is something as simple as wearing contact lenses for too long, or staring at a computer screen for lengthy periods of time without a break. Other causes include, among others: allergies, blepharitis (inflamed eyelid), conjunctivitis (pink eye), dry eye, eye injury, or glaucoma.
- Allergies: When an irritating substance (such as pollen, pet dander, dust, or certain chemicals found in makeup or contact lens solutions) gets into a person’s body, the immune system reacts. The body releases histamine to fight off the allergens, which causes blood vessels in the eyes to enlarge, and eyes become red, watery, and itchy.
- Blepharitis (inflamed eyelid): This is a common condition that causes the eyelid to become red and inflamed. In addition to a red, swollen eyelid, the eye may also burn, itch, be sensitive to light, and have excessive tears.
- Conjunctivitis (pink eye): Conjunctivitis is one of the most common eye infections, especially among children. It occurs when the conjunctiva, the thin, transparent membrane that covers the white of the eye and lines the eyelids, gets infected. When the conjunctiva is infected, the blood vessels inside it become irritated and swell, making the eye look red or pink. Many times the eyelids also emit a sticky discharge, and eyelashes can stick together.
There are different types of pink eye. Viral eye infections, the most common, tend to improve on their own, and don’t require prescription medication. Bacterial eye infections require antibiotics. Both types of infection, particularly viral, are contagious and spread easily.
Children are most likely to get pink eye because they are in close contact with others in school or day care centers. Because some types of pink eye are contagious, it is important to see a doctor for correct diagnosis and treatment of the infection. Family physicians or pediatricians can diagnose and treat some eye infections.
- Dry eye: When eyes do not produce enough tears, or produce tears that lack the lipid part, dry eye is the result. Adequate and well-functioning tears are needed for eyes to be healthy and comfortable. Dry eye symptoms include stinging or burning, lots of tears followed by periods of dryness, and possible mucus discharge. The condition may be painful, and eyes may be red. Men and women can get dry eye, although it is more common in women, especially those who have gone through menopause. As people age, they produce less of the lipid part of the tears, which puts them at greater risk for dry eye. Dry eye is also a side effect of taking certain medicines. The condition initially can be managed by moistening eyes with artificial tears eye drops.
- Eye injury: A trauma or an injury to the eye can cause red, bloodshot eyes. Blood vessels in the eye dilate (open) to allow more blood to get to the injury site for quicker healing. These open blood vessels are what cause the red eye. Eye injuries can include corneal abrasions (scratches to the surface of the eye), puncture wounds, and chemical burns. These eye injuries need immediate medical attention and should be treated as a medical emergency.
- Glaucoma: In most cases, glaucoma comes on gradually and usually does not have symptoms at first. Acute or severe glaucoma is a sight-threatening condition that needs urgent medical attention. Be alert to suddenly painful, bright-red eyes, accompanied by seeing halos around lights, vision loss, and nausea.
In addition, red eye can also stem from other causes:
- Excessive alcohol use, which reduces oxygen to red blood cells. This causes blood vessels to clump together and makes eyes appear red and bloodshot.
- Smoking increases the risk of eye diseases that affect a person’s vision. Tobacco smoke is also a toxic eye irritant that can cause dry, red, and itchy eyes. Smoking marijuana also causes red, bloodshot eyes. An ingredient in marijuana causes the blood vessels in the eye to dilate, producing red eye that can last for hours or longer.
- Whitening eye drops that claim to whiten eyes contain vasoconstrictors, or chemicals that shrink the blood vessels on the surface of the eye to reduce redness. The drops do get rid of red eye, but the fix is temporary. Many people who regularly use these types of eye drops build up a resistance to their whitening effects, which means that they will need to use more and more drops each time to achieve the same results.
Care and Treatment
What are the treatments for red eye?
Remedies for red eye are wide-ranging. Many times, rest, cool compresses over closed eyes, lightly massaging the eyelids, gently washing the eyelids, and/or over-the-counter eye drops, can relieve the symptoms. Other times, an eye doctor may recommend and prescribe antibiotics, special eye drops, or ointments.
Treatments for specific conditions include the following:
- Red eye due to allergies. In addition to avoiding the allergen (if it is known), treatment usually consists of over-the-counter eye drops. Using artificial tear drops will wash allergens from the eye and add moisture to relieve dry, irritated eyes. Decongestant eye drops reduce redness in the eyes from allergies. Decongestant eye drops with an antihistamine will also help relieve itchiness.
- Blepharitis. Treatment usually involves keeping the eyelids clean. Wetting a washcloth with warm water, wringing out excess water, and holding it to the closed eyelid(s) for several seconds can help relieve symptoms. Dipping a cotton swab into a mixture of water and baby shampoo to lightly wash the eyelid will also help. Once the condition occurs, it usually does not go away completely, so it is important to clean the eyelids regularly. In some cases, the eye doctor may also prescribe antibiotics or steroid eye drops.
- Bacterial or viral pink eye:
- Place a warm, damp washcloth over the infected, closed eye for a few minutes. This will also loosen dried mucus if eyelashes or eyelids are sticking together.
- Use a clean washcloth each time so the infection does not spread.
- If the pink eye is in both eyes, use a different washcloth for each eye.
- Use over-the-counter lubricating eye drops (artificial tears).
How can red eye be prevented?
- Don't rub the eyes. Dirt and germs on the hands and fingers can cause even more redness and irritation.
- Keep contact lenses clean, and do not wear them longer than recommended.
- Remove eye makeup properly and keep eyes clean.
- Take regular breaks when looking at the computer screen for long periods of time.
- Schedule an eye exam to make sure the cause of red eye is not something more serious.
When to Call the Doctor
When should red eye be treated by an ophthalmologist?
Although red eye usually goes away on its own, redness of the eye sometimes can signal a more serious eye condition or disease. Contact an ophthalmologist for diagnosis and treatment if:
- Eyes are painful
- Vision is affected
- Eyes become extra sensitive to light
- Symptoms have continued for a week or more, or are getting worse
- The eye is producing a lot of pus or mucus
- A fever or aches are also present with the eye discomfort
If red eye is accompanied by eye pain, light sensitivity, swelling, or blurry vision, it is important to make an appointment with an eye doctor immediately for treatment.
The ophthalmologist may recommend the use of artificial tears. These eye drops act like a body’s own tears. Artificial tears are available without a prescription and can be used as often as necessary.
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