What is Trachoma?
Trachoma is the world’s leading cause of preventable blindness and the second cause of blindness after cataract. Blindness from trachoma occurs after years and years of repeated infection with the microorganism, Chlamydia trachomatis. This process of infection and reinfection begins in early childhood and may continue to adulthood, if the cycle is not broken. Repeated infection and inflammation lead to scarring of the conjunctiva, which may eventually cause the eyelid to turn inwards. As the eyelid turns inward, eye lashes begin to scratch the cornea (trichiasis). In addition to Chlamydia trachomatis, other organisms of a bacterial or fungal nature may also be present. The irritation and aggravation of the cornea leads to corneal opacities that impair vision. In hyperendemic communities, vision loss and blindness may occur in relatively young adults.
Women have two-to-three times the rate of advanced trachoma and blindness than men, because as mothers, grandmothers and older sisters who care for children (the main source of active trachoma infection), they are excessively and continually exposed to the bacterium. Crowded living conditions, lack of sufficient water and sanitation services, and contact with eye-seeking flies and fly-breeding sites near the homes are some of the many risk factors for trachoma. Trachoma is an indicator of public health and community health issues as well as a pathway to blindness for many individuals.
How is trachoma transmitted and who is at risk for trachoma?
Trachoma is transmitted person-to-person by ocular and respiratory secretions. It is frequently passed from child-to-child and from child-to-mother within the family. Infection usually first occurs in childhood but people do not became blind until they are adults. The disease progresses over years as repeated infections cause scarring on the inside of the eyelid. The eyelashes eventually turn in. This causes rubbing on the cornea (the covering over the pupil and iris). The cornea becomes scarred, leading to severe vision loss and eventually blindness, mainly in adult women. However, in highly endemic areas children of both sexes, as young as nine or ten years of age, have been known to require trichiasis surgery.
While trachoma has an ancient history and has existed as a problem in many parts of the world (including Europe and the USA), it is no longer a blinding problem except in countries located primarily in Africa, the Middle East, and parts of Asia.
What are the symptoms of trachoma?
The World Health Organization and its advisors recommend use in the field of the simplified trachoma grading scheme. When a child living in a trachoma-endemic area complains of watery eyes, thick secretions, irritation and soreness, the scheme can be used to determine if the child has trachoma. The eyelid is flipped and the tarsal conjunctiva examined for TF, TI and TS. The lid itself is examined for in-turning lashes (TT) in usual and unusual sectors. Finally, the cornea is examined for CO:
- TF : Trachomatous Inflammation—Follicular. The presence of five (5) or more follicles (follicles are small, round, whitish swellings or dots) visible in the upper tarsal conjunctiva.
- TI : Trachomatous Inflammation—Intense. Pronounced inflammatory thickening of the tarsal conjunctiva that obscures more than half the normal deep tarsal vessels.
- TS : Trachomatous Scarring. The presence of scarring in the tarsal conjunctiva
- TT: Trachomatous Trichiasis. At least one eyelash rubs on the eyeball.
- CO: Corneal Opacity. Easily visible corneal opacity over the pupil.
The presence of these signs indicates active and/or chronic trachoma.
What can be done to prevent and control trachoma and eliminate it as a cause of blindness?
Trachoma is a disease of marginalized populations living in areas with limited resources and in need of a good water supply near their home as well as proper, well-maintained sanitation facilities. As the education and economic welfare of a community rises, trachoma decreases. Meanwhile, the WHO, along with an alliance of interested parties, Alliance for Global Elimination of Trachoma by the year 2020 (GET 2020; World Health Organization's Prevention of Blindness and Deafness) has adopted the “SAFE” strategy to combat trachoma. The four components of the strategy include:
S urgery – to correct end-stage disease
A ntibiotic treatment - tetracycline eye ointment, Zithromax® (azithromycin), etc.
F acial cleanliness – frequent face washing
E nvironmental Improvement – improved water supply and sanitation facilities
What treatment is available for trachoma?
As stated above, improving the quality of life will interrupt the transmission dynamics and limit this disease. The SAFE Strategy is designed to address the risk of acquiring trachoma and therefore address “treatment.”
Where can I get more information?
World Health Organization Alliance for Global Elimination of Trachoma by the year 2020 (GET 2020)