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 ischaracterized 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 and 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

Resources

BOOKS

Riordan-Eva, Paul, et al. "Eye." In Current Medical Diagnosis and Treatment, 1998, edited by Stephen McPhee, et al., 37th ed. Stamford: Appleton & Lange, 1997.

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.

TRACHOMA

Trachoma is a virulent form of conjunctivitis caused by Chlamydia trachomatis, a bacterial organism transmitted by flies that crawl into the eyes of small children. Direct transmission of the organism from fingers, damp towels, and other objects also occurs. Characteristically, reinfection is frequent in endemic regions; this leads to severe scarring and contractures, especially of the upper eyelid, and also causes blood vessels to invade the cornea, rendering it opaque. These effects of recurrent infection make trachoma a leading cause of blindness in those parts of the world where the condition is prevalent. These are predominantly poor, rural areas in hot, dry countries such as some nations in the Middle East and in arid regions of North Africa, India, Pakistan, and inland Australia.

Trachoma is responsible for about 6 million out of a total of 20 million cases of blindness worldwide, and it causes impaired vision in about 140 million people. Determined efforts have greatly reduced the incidence of new cases in the last two decades of the twentieth century, however. It is rare in industrially developed nations with good hygiene and effective fly control measures—such as screened windows. Trachoma is an exclusively human infection, so if vulnerable populations can be protected from exposure (e.g., if flies can be reduced or eliminated), transmission will cease and the infection can be prevented. These tactics have worked well in many regions, including among Australian Aborigines, where the prevalence was very high until control programs were established.

Control was achieved in Australia by an aggressive campaign led by Dr. Ida Mann, who devoted her life to this cause. Her methods comprised topical application of antiseptic and antibiotic eyedrops, disinfection and face washing, education about personal hygiene, and fly control programs. Initially this was a mass campaign, and it was reduced to individual case management as endemic conjunctivitis was brought under control. The same tactics have worked in the Middle East (e.g., among nomadic Bedouin populations in Saudi Arabia), and they are working well in endemic regions of India and Pakistan. The World Health Organization, with strong support from several foundations and nongovernmental organizations devoted to prevention of blindness, aspires to eliminate trachoma by 2020.

John M. Last

(see also: Vision Disorders )

trachoma , infection of the mucous membrane of the eyelids caused by the bacterium Chlamydia trachomatis. Trachoma infects more than 150 million people worldwide. An estimated 6 million people have become blind because of it, making the disease the second leading cause of blindness, after cataracts. It is most common in parts of Africa, the Middle East, and Asia. In the United States it has occurred sporadically among Native Americans and in mountainous areas of the South.

Trachoma is highly contagious in its early stages and is transmitted by direct contact with infected persons or articles (e.g., towels, handkerchiefs) and possibly also by flies. It begins as congestion and swelling of the eyelids with tearing and disturbance of vision. The cornea is often involved. If left untreated, scar tissue forms, which causes deformities of the eyelids and, if there is corneal involvement, partial or total blindness. The disease has been effectively treated with tetracycline ointment and with the newer oral drug azithromycin (Zithromax). The World Health Organization began a campaign in 1998 to eradicate the disease worldwide by the year 2020. The strategy includes use of azithromycin and sanitation improvements in water supplies.

trachoma (tră-koh-mă) n. a chronic contagious eye disease – a severe form of conjunctivitis caused by the bacterium Chlamydia trachomatis – that is common in some hot countries. If untreated, the conjunctiva becomes scarred and shrinks, causing trichiasis; blindness can be a late complication. Treatment with tetracyclines is effective in the early stages of the disease.

trachoma Chronic eye infection caused by the microorganism Chlamydia trachomatis, characterized by inflammation of the cornea with the formation of pus. A disease of dry, tropical regions, it is the major cause of blindness in the developing world.