A Closer Look

What is Conjunctivitis?


Conjunctivitis is the term used to describe inflammation of the conjunctiva — the thin, filmy membrane that covers the inside of your eyelids and the white part of your eye (sclera). Conjunctivitis is most commonly referred to as "pink" eye.

The conjunctiva, which contains tiny blood vessels, produces mucus to coat and lubricate the surface of your eye. When the conjunctiva becomes irritated or inflamed, the blood vessels become larger and more prominent, making your eye appear red. Conjunctivitis may occur in one or both eyes.

What Are the Symptoms of Conjunctivitis?

Symptoms of conjunctivitis include:

  • Increased tearing
  • Soreness of the eye
  • Foreign body sensation
  • Itchiness of the eye
  • Hazy or blurred vision due to mucus or pus
  • Excess mucus (pus)
  • Crusting of eyelashes in the morning

What Causes Conjunctivitis?

Many different sources of eye irritation can cause conjunctivitis. The most common are:

  • Infections (viral and bacterial)
  • Allergies
  • Environmental irritants

Viral infection is the most common cause of conjunctivitis. This same virus produces the familiar red and watery eyes, sore throat and runny nose of a common cold. Symptoms of conjunctivitis can last from one to two weeks and then will disappear on their own. Discomfort, however, can be alleviated with warm compresses applied to the eyes. Prescription eyedrops may be prescribed by your ophthalmologist (Eye M.D.) to help minimize drainage or discomfort.

Bacterial infections, such as Staphylococcus or Streptococcus, cause a type of pink eye that produces considerable amounts of pus. Some bacterial infections, however, are more chronic and may produce little or no discharge except for some mild crusting of the eyelashes in the morning. Antibiotic eyedrops are typically used to treat bacterial conjunctivitis.

Infectious conjunctivitis, whether bacterial or viral, is highly contagious while the eyes are draining. Practicing good hygiene can help prevent the spread of conjunctivitis if you are infected. You should:

  • Avoid reusing handkerchiefs and towels to wipe your face and eyes
  • Wash your hands frequently
  • Keep your hands away from your eyes
  • Replace your eye cosmetics regularly -- do not share with other people
  • Properly clean your contact lenses

Allergic Conjunctivitis

Allergic conjunctivitis is not infectious or contagious. It occurs when the body is exposed to materials that cause an allergic reaction, such as pollen or dander, and is often seasonal. The main symptom of allergic conjunctivitis is itchiness of the eye. Other symptoms include redness, burning tearing and puffy eyelids.

A variety of eyedrops are very helpful for allergic conjunctivitis. Your ophthalmologist can help you decide if an over-the-counter or a prescription drop is best for you.

Environmental Irritants

Irritants, such as smoke or fumes, may also cause conjunctivitis. The symptoms are usually similar to those of allergic conjunctivitis.

Other Causes of Red Eyes

Generally, conjunctivitis is easily treated. However, if symptoms of conjunctivitis persist for an extended period of time after treatment, you should have your eyes examined by your ophthalmologist, as these symptoms may indicate a more serious eye problem. There are several eye diseases that cause red eyes, some of which can lead to blindness unless diagnosed and treated.