Trachoma

DEFINITION

Trachoma (truh-KOH-muh) is a bacterial infection that affects your eyes. The bacterium that causes trachoma spreads through direct contact with the eyes, eyelids, and nose or throat secretions of infected people.

Trachoma is very contagious and almost always affects both eyes. Signs and symptoms of trachoma begin with mild itching and irritation of your eyes and eyelids and lead to blurred vision and eye pain. Untreated trachoma can lead to blindness.

If trachoma is treated early, it often may prevent further trachoma complications.

CAUSES

Trachoma is caused by certain subtypes of Chlamydia trachomatis, a bacterium that can also cause the sexually transmitted infection chlamydia.

Trachoma spreads through contact with discharge from the eyes or nose of an infected person. Hands, clothing, towels and insects can all be routes for transmission. In the world’s developing countries, flies are a major means of transmission.

SYMPTOMS

The principal signs and symptoms in the early stages of trachoma include:

• Mild itching and irritation of the eyes and eyelids
• Discharge from the eyes containing mucus or pus

As the disease progresses, later trachoma symptoms include:

• Marked light sensitivity (photophobia)
• Blurred vision
• Eye pain

Young children are particularly susceptible to infection, but the disease progresses slowly, and the more painful symptoms may not emerge until adulthood.

The World Health Organization has identified a grading system with five stages in the development of trachoma, including:

• Inflammation — follicular. The infection is just beginning in this stage. Five or more follicles — small bumps that contain lymphocytes, a type of white blood cell — are visible with magnification on the inner surface of your upper eyelid (conjunctiva).
• Inflammation — intense. In this stage, your eye is now highly infectious and becomes irritated, with a thickening or swelling of the upper eyelid.
• Eyelid scarring. Repeated infections lead to scarring of the inner eyelid. The scars often appear as white lines when examined with magnification. Your eyelid may become distorted and may turn in (entropion).
• Ingrown eyelashes (trichiasis). The scarred inner lining of your eyelid continues to deform, causing your lashes to turn in so that they rub on and scratch the transparent outer surface of your eye (cornea).
• Corneal clouding. The cornea becomes affected by an inflammation that is most commonly seen under your upper lid. Continual inflammation compounded by scratching from the in-turned lashes leads to clouding of the cornea. Secondary infection can lead to development of ulcers on your cornea and eventually partial or complete blindness.

All the signs of trachoma are more severe in your upper lid than in your lower lid. With advanced scarring, your upper lid may show a thick line. In addition, the lubricating glandular tissue in your lids — including the tear-producing glands (lacrimal glands) — can be affected. This can lead to extreme dryness, aggravating the problem even more.

When to see a doctor

Call your doctor if you or your child has itching, irritation or discharge from the eyes, especially if you recently traveled to an area where trachoma is common. Trachoma is a contagious condition, and it should be treated as soon as possible to prevent further infections.