Conjunctivitis

Eye

Alternative names

Inflammation - conjunctiva; Pink eye

Definition 

Conjunctivitis is inflammation or infection of the membrane lining the eyelids (conjunctiva).

Causes and risks

The conjunctiva is exposed to bacteria and other irritants. Tears help protect the conjunctiva by diluting bacteria and washing it away. Tears also contain enzymes and antibodies which kill bacteria.

There are many causes of conjunctivitis. Viruses are the most common cause. Other types include bacterial, Chlamydial, fungal, and parasitic agents (rarely).

Pink eye refers to a viral infection of the conjunctiva. These infections are very contagious, especially among children.  The virus is similar to the type which cause the common cold.  The key is handwashing to prevent spreading the virus. 

Bacteria are an uncommon cause of conjunctivitis. Many physicians will give a mild anitbiotic eyedrop for all cases of pink eye to prevent bacterial conjunctivitis.  Other causes are allergies (allergic conjunctivitis), chemical exposure, and certain systemic diseases.

Newborns can be infected by bacteria in the birth canal. This condition is called ophthalmia neonatorum, and it must be treated immediately to preserve sight. Use of contact lenses, particularly extended-wear lenses, can cause conjunctivitis.

See also:

• Keratoconjunctivitis sicca
• Viral conjunctivitis
• Allergic conjunctivitis
• Vernal conjunctivitis
• Trachoma
• Neonatal conjunctivitis

Prevention

Good hygiene can help prevent the spread of conjunctivitis:

• Keep hands away from the eye.
• Wash the hands frequently.
• Change pillowcases frequently.
• Replace eye cosmetics regularly.
• Do not share eye cosmetics.
• Do not share towels or handkerchiefs.
• Proper use and care of contact lenses.

Symptoms

• Tearing, increased
• Eye pain
• Redness in the eyes
• Gritty feeling in the eyes
• Itching of the eye
• Blurred vision
• Sensitivity to light
• Crusts that form on the eyelid overnight

Signs and tests

• Examination of eyes
• Swab of conjunctiva for analysis

Treatment   

Treatment of conjunctivitis depends upon the cause.

Allergic conjunctivitis may respond to treatment for underlying allergies, or it may disappear on its own when the causative allergen is removed. Cool compresses may be soothing for allergic conjunctivitis.

Antibiotic medication, usually eye drops, is effective for bacterial conjunctivitis. Viral conjunctivitis will disappear on its own. The discomfort with viral or bacterial conjunctivitis can be soothed by applying warm compresses (a clean cloth soaked in warm water) to closed eyes.

Prognosis

The outcome is usually good with treatment.