The conjunctiva is the thin, filmy membrane that covers the white of the eye (sclera). The conjunctiva serves to produce mucus to coat and lubricate the surface of the eye. When irritated, the fine blood vessels within the conjunctiva become enlarged, and the eye turns red. The most common sources of eye irritation resulting in conjunctivitis are infections, allergies, and environmental irritants.
What Causes Conjunctivitis?
Infectious causes of conjunctivitis include bacteria and viruses. Viruses are a more common cause. Bacterial infections, such as staphylococcus or streptococcus, cause a red eye which is associated with considerable amounts of pus. If the amount of discharge from the eye is great, an acute infection is likely, and prompt consultation with an ophthalmologist is advisable. On the other hand, some bacterial infections are more chronic and may produce little or no discharge except for some mild crusting of the eyelashes in the morning.
Viruses are also common causes of conjunctivitis. Some viruses produce the familiar red eyes, sore throat, and runny nose of a common cold. Others may infect only one eye. Viral conjunctivitis usually produces a watery discharge and lasts from one to two weeks.
Infectious conjunctivitis, whether bacterial or viral, can be quite contagious, so contact with the patient's tears through used handkerchiefs and towels should be avoided. Handwashing after contact with the patient helps to prevent spread of the infection.
Allergies tend to cause a type of conjunctivitis which produces a discharge. Some kinds of allergies, like hay fever, make the eyes very itchy, while others may merely produce a chronic redness. Finally, environmental irritants such as smoke or fumes may cause conjunctivitis. Any type of conjunctivitis is aggrevated by dryness of the eyes.
What Are Other Causes Of Red Eyes?
There are several eye diseases which also produce a red eye and which can lead to blindness unless recognized and treated. It is important to avoid confusing them with conjunctivitis. Symptoms of pain, blurred vision, or severe light sensitivity are typically not found in simple conjunctivitis but may be a signal for the presence of glaucoma, an ulcer of the eye, or an inflammation of the inside of the eye.
Treatment:
Bacterial conjunctivitis requires cleaning the discharge from the eyelids and then instilling the appropriate abtibiotics. For viral conjunctivitis, except Herpes simplex, there are no antiviral treatments available. Symptomatic relief can be obtained by using cold compresses and topical decongestants such as Clear Eyes. Allergic conjunctivitis can be treated with over the counter drops, such as Upcon A, or prescription drops. When drops are instilled into the eyes, the eyelids should be closed for a few minutes. Remember to wash hands thoroughly after instilling the drops.
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