– An inflammation or infection of the conjunctiva of the eye.

Causes and Incidence

Causes include viruses, bacteria, airborne or contact allergens, and environmental irritants (e.g., sun, wind, dust, smog, smoke, noxious gases). Conjunctivitis is common and is easily spread when bacterial or viral in nature.

Disease Process

The severity varies by exposure and cause. The etiologic agent comes in contact with and irritates the conjunctiva, setting up an inflammatory response. Recurrent inflammation leads to thickening of the conjunctival layer and lid margins.


Bacterial type
Purulent drainage, lid swelling, moderate discomfort, redness of conjunctiva

Viral type
Clear discharge, swollen preauricular node, tearing, redness, moderate discomfort, light sensitivity

Allergen or irritant
Clear discharge, profuse tearing, feeling of something in the eye, intense itching (allergen), severe swelling of the lid, generalized redness of the eye, moderate burning feeling

Potential Complications If left untreated, infection may spread from conjunctiva to cornea and cause ulceration, perforation, and blindness.

Diagnostic Tests

Smears and cultures of discharge are done to determine if viral or bacterial agent is present. Conjunctival scrapings are used to rule out inclusion conjunctivitis, trachoma, and vernal conjunctivitis. Vision, intraocular pressure, cornea, iris, pupil, and pupillary response are all normal.



Topical antiinfective drugs for bacterial cause; topical antivirals for viral cause; topical corticosteroids for allergens.

Saline irrigation for discharge and comfort; warm compresses for inflammation, cool compresses for itching.