Trachoma results from infections with certain nonsexually transmitted strains of Chlamydia trachomatis. Trachoma is common in dry, hot countries in North Africa, the Middle East, the Indian subcontinent, Australia, and Southeast Asia. In the United States, trachoma is rare, occurring occasionally among Native Americans and among immigrants from areas where trachoma is common. Trachoma is the leading preventable cause of blindness in the world.
The disease occurs mainly in children, particularly those between the ages of 3 and 6. Older children and adults are much less likely to have the disorder because of increased immunity and better personal hygiene.
Trachoma is contagious in its early stages and may be transmitted by eye–hand contact, by flies, or by sharing contaminated articles, such as towels, handkerchiefs, and eye makeup.
Trachoma usually affects both eyes. The conjunctivae (the membranes that line the eyelid and cover the white of the eye) become inflamed, red, and irritated, and the eyes water excessively. The eyelids swell. Sensitivity to bright light occurs.
In the later stages, blood vessels may gradually grow across the cornea (called neovascularization), obstructing vision. In some people, the eyelid is scarred in such a way that the eyelashes turn inward (trichiasis). As the person blinks, the eyelashes rub against the cornea, causing infection and often permanent damage. Impaired vision or blindness occurs in about 5% of people with trachoma.
Doctors suspect trachoma based on the appearance of the eyes and on the duration of symptoms. The diagnosis of trachoma can be confirmed by swabbing the eye and sending the sample to a laboratory, where the infecting organism is identified.
Because trachoma is contagious, reinfection commonly occurs. Access to water that is suitable for drinking (potable) can reduce reinfection. Regular hand and face washing helps prevent spread. Sharing towels, washcloths, bedding, and eye makeup should be avoided. Because flies can transfer the disease among people, places where flies can breed should be eliminated.
Treatment of trachoma consists of an antibiotic (such as azithromycin, doxycycline, or tetracycline) taken by mouth. Alternatively, tetracycline or erythromycin can be applied as an ointment. Doctors often give antibiotics to entire neighborhoods where there are many people with trachoma. If the condition damages the eyelid, conjunctiva, or cornea, surgery may be needed.