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.
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.
trachoma
[trah-ko´mah] (pl. tracho´mata) a chronic infectious disease of the conjunctiva and cornea, producing
photophobia, pain, and
lacrimation, caused by an organism once thought to be a virus but now classified as a strain of the bacteria
Chlamydia trachomatis. It is more prevalent in Africa and Asia than in other parts of the world; in North Africa few persons reach adulthood without having contracted the infection. It is fairly common in parts of the United States, such as in parts of the Southwest where a hot dry climate and scarcity of water encourage its spread. Trachoma in children and adults begins with a conjunctivitis that is marked by tiny follicles on the upper eyelids and tarsal plate. The follicles become larger and larger, and there is granulation of the cornea and impairment of vision. Eventually there is severe scarring which results in
blindness. Trachoma is the world's leading cause of preventable
blindness.
A condition closely related to trachoma in cause, manifestations, and epidemiologic pattern is
inclusion conjunctivitis, which is fundamentally a sexually-transmitted disease of the adult genital tract. The agents of trachoma and inclusive conjunctivitis are called
tric agents.
Treatment and Prevention. The drug of choice in treatment of trachoma is
azithromycin; studies have demonstrated that a single oral dose eliminates the infection and prevents scarring. In areas where
azithromycin is not available, tetracyclines may be used, administered topically in the form of suspensions or ointments that adhere to the conjunctiva for prolonged effect. Prevention of trachoma begins with an adequate water supply for washing the hands and bathing, control of flies, and education of the local population about the cause and spread of the disease. Early treatment of young children reduces the source of infection and avoids the complication of blindness. Repeated treatment programs for adults help control the spread of infection.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.