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Red eyes can be the sign of a minor irritation or a serious medical condition, such as an infection.

Bloodshot or red eyes occur when small blood vessels that are present on the surface of the eye become enlarged and congested with blood. This happens due to an insufficient amount of oxygen being supplied to the cornea or the tissues covering the eye.

Bloodshot eyes by themselves are generally not a reason to be overly concerned, but when coupled with eye pain, abnormal drainage, or impaired vision this can indicate a serious medical problem.

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Conjunctivitis is also known as pink eye and is mostly caused by viruses, which may be spread by the hands.

Conjunctivitis, commonly known as pinkeye, is an infection that includes swelling and irritation of the conjunctiva. The conjunctiva is a thin transparent membrane that lines the eyelid and loops back to cover the the white part of the eye.

An infection of the conjunctiva irritates the blood vessels causing them to swell up. It is this inflammation that makes the whites of the eyes appear reddish or even a bit pink.

Viruses cause up to 80 percent of all cases of conjunctivitis. Pink eye is prevalent among school children and is very contagious.

The infection is commonly spread through direct contact with contaminated fingers or personal items. It is often associated with an upper respiratory infection and spread through coughing.

Allergic conjunctivitis can be due to an allergy or an irritant such as dust. Wearing contact lenses for too long or not properly cleaning them can also lead to conjunctivitis. Conjunctivitis caused by allergies or irritants is not contagious.

People usually end up getting pink eye in both eyes because an infection can easily spread from one eye to the other. Signs and symptoms of conjunctivitis include:

  • itchy eye
  • excess tear production
  • redness
  • discharge
  • light sensitivity
  • poor vision
  • gritty feeling in one or both eyes

A doctor can typically spot conjunctivitis due to the telltale reddish-pink eye or by the type of discharge present. People with bacterial conjunctivitis may not have the red eye but are likely to have a distinctive mucus discharge or drainage that is white, green, or yellow.

To confirm the diagnosis, a doctor may do a full eye examination or take a sample of any eye discharge for laboratory analysis.

If the outbreak is due to an allergy, a doctor may order an allergy test to determine the specific allergen that the person needs to avoid.

Treatment options for conjunctivitis depend on the type, so it is important to see a doctor if experiencing any of the signs and symptoms. Pink eye is not a serious condition and it does not typically cause any long-term vision problems. It will often clear up on its own.

To avoid spreading conjunctivitis, people should wash their hands frequently and avoid rubbing their eyes. They should also avoid sharing eye drops, cosmetics, towels, or pillowcases.

After bacterial or viral conjunctivitis clears up, people should dispose of any contact lenses, solutions, or eye makeup they used while they were infected to help avoid re-infection.

Red eyes can develop suddenly or over time. Eye drops are helpful in many cases, and can be purchased over-the-counter or online. If the redness is not easing up and is accompanied by other symptoms, people should see a doctor.

Eye injuries, contact lenses, and frequent use of eye drops can all cause irritation leading to red eyes. A doctor can help a person to pinpoint the cause of their red eye problem and develop a treatment plan.

Common treatments include eye drops, antibiotics, creams, and oral medications. Most conditions are readily treatable and, if caught early, do not cause any permanent long-term damage.

Some serious medical conditions, including leukemia, sarcoidosis, and juvenile idiopathic arthritis, can also cause a red eye. As a result, getting a proper diagnosis is critical.

People should not hesitate to contact their doctor with any questions or concerns if they have red eyes.