Trachoma

Definition

Trachoma, which is also called granular conjunctivitis or Egyptian ophthalmia, is a contagious, chronic inflammation of the mucous membranes of the eyes, caused by Chlamydia trachomatis. It is characterized by swelling of the eyelids, sensitivity to light, and eventual scarring of the conjunctivae and corneas of the eyes.

Description

Trachoma is a major cause of blindness in the world. It is found in the Far East, as well as countries with desert climates. In the United States, it is most common among certain Native Americans and in parts of Appalachia. The infection is highly contagious in its early stages. Blindness results from recurrent untreated infections.

The conjunctiva is the clear mucous membrane that lines the inside of the eyelid and covers the white part (sclera) of the eye. Conjunctivitis is an inflammation of the conjunctiva.

Causes & symptoms

Trachoma is caused by C. trachomatis, a parasitic organism closely related to bacteria. It is transmitted by insects, by hand-to-eye contact, or by the sharing of infected handkerchiefs or towels. The incubation period is about a week.

The early symptoms of trachoma include the development of follicles (small sacs) on the conjunctivae of the upper eyelids, pain, swollen eyelids, a discharge, tearing, and sensitivity to light. If the infection is not treated, the follicles develop into large yellow or gray pimples, and small blood vessels develop inside the cornea. In most cases, both eyes are infected.

Repeated infections eventually lead to contraction and turning in of the eyelids, scarring of the corneas and conjunctivae, eventual blockage of the tear ducts, and blindness.

Diagnosis

Diagnosis is based on a combination of the patient's history (especially living or traveling in areas with high rates of trachoma) and examination of the eyes. The doctor will look for the presence of follicles or scarring. He or she will take a small sample of cells from the patient's conjunctivae and examine them following a procedure called Giemsa staining to confirm the diagnosis.

Treatment

Treatment of early-stage trachoma consists of four to six weeks of antibiotic treatment with tetracycline, erythromycin, or sulfonamides. Antibiotics should be given without waiting for laboratory test results. Treatment may combine oral medication with antibiotic ointment applied directly to the eyes. A single-dose treatment with azithromycin is an alternative method. Tetracyclines should not be given to pregnant women or children below the age of seven years.

Patients with complications from untreated or repeated infections are treated surgically. Surgery can be used for corneal transplantation or to correct eyelid deformities.

Prognosis

The prognosis for full recovery is excellent if the patient is treated promptly. If the infection has progressed to the stage of follicle development, prevention of blindness depends on the severity of the follicles, the presence of additional bacterial infections, and the development of scarring.

Prevention

There are vaccines available that offer temporary protection against trachoma, but there is no permanent immunization. Prevention depends upon good hygiene and public health measures:

• Seek treatment immediately if a child shows signs of eye infection, and minimize his or her contact with other children.
• Teach children to wash hands carefully before touching their eyes.
• Protect children from flies or gnats that settle around the eyes.
• If someone has trachoma (or any eye infection), do not share towels, pillowcases, etc. Wash items well.
• If medications are prescribed, follow the doctor's instructions carefully.

Key Terms

Conjunctivitis

Inflammation of the conjunctivae, which are the mucous membranes covering the white part of the eyeball (sclera) and lining the inside of the eyelids.

Cornea

The transparent front part of the eye that allows light to enter.

Ophthalmia

Inflammation of the eye. Usually severe and affecting the conjunctiva. Trachoma is sometimes called Egyptian ophthalmia.

Further Reading

For Your Information

Books

• O'Brien, Terrence P., "Conjunctivitis." In Conn's Current Therapy, edited by Robert E. Rakel. Philadelphia: W. B. Saunders Company, 1998, p.70.
• "Ophthalmologic Disorders: Trachoma." In The Merck Manual of Diagnosis and Therapy, vol. II, edited by Robert Berkow, et al. Rahway, NJ: Merck Research Laboratories, 1992, p.2372-2373.
• Riordan-Eva, Paul, et al., "Eye." In Current Medical Diagnosis & Treatment 1998, edited by Lawrence M. Tierney, Jr., et al. Stamford, CT: Appleton & Lange, 1997.
• "Trachoma." In Professional Guide to Diseases, edited by Stanley Loeb, et al. Springhouse, PA: Springhouse Corporation, 1991.

Gale Encyclopedia of Medicine. Gale Research, 1999.