Priority eye diseases
Trachoma is one of the oldest infectious diseases known to mankind. It is caused by Chlamydia trachomatis – a microorganism which spreads through contact with eye discharge from the infected person (on towels, handkerchiefs, fingers, etc.) and through transmission by eye-seeking flies. After years of repeated infection, the inside of the eyelid may be scarred so severely that the eyelid turns inward and the lashes rub on the eyeball, scarring the cornea (the front of the eye). If untreated, this condition leads to the formation of irreversible corneal opacities and blindness.
Trachoma affects about 21.4 million people of whom about 2.2 million are visually impaired and 1.2 milion are blind. It was once endemic in most countries. It is responsible, at present, for more than 3% of the world’s blindness but the number keeps changing due to the effect of socioeconomic development and current control programmes for this disease. In spite of this, trachoma continues to be hyperendemic in many of the poorest and most remote poor rural areas of Africa, Asia, Central and South America, Australia and the Middle East. The sequelae of active trachoma appear in young adulthood and in middle-aged persons. In hyperendemic areas active disease is most common in pre-school children with prevalence rates as high as 60-90%. It often strikes the most vulnerable members of communities--women and children. Adult women are at much greater risk of developing the blinding complication of trachoma than are adult men. This increased risk has been explained by the fact that women generally spend a greater time in close contact with small children, who are the main reservoir of infection.
Since May 2011, the WHO Global Health Observatory provides online access to the national data on trachoma prevalence and relevant maps.
- Weekly Epidemiological Record 2013
Trachoma Monitoring Form 2013: Summary
- Weekly Epidemiological Record 2012
- Access data on Trachoma in Global Health Observatory
- Trachoma maps (Global Atlas)
Mapping the global distribution of trachoma
Prevention and treatment
Environmental risk factors are water shortage, flies, poor hygiene conditions, and crowded households. A prolonged exposure to infection throughout childhood and young adulthood appears to be necessary to produce the complications seen in later life. A single episode of acute Chlamydial conjunctivitis is not considered sight threatening as there is virtually no risk of prolonged inflammation or blinding complications.
A Global Partnership for Trachoma Elimination
A global initiative to eliminate trachoma as a blinding disease, entitled GET 2020 (Global Elimination of Trachoma), was launched under WHO’s leadership in 1997. Through this initiative control activities are instituted through primary health care approaches that follow the evidence-based “SAFE” strategy. This consists of lid surgery (S), antibiotics to treat the community pool of infection (A), facial cleanliness (F); and environmental changes (E). VISION 2020 national plans that address trachoma are written in line with the GET2020 "SAFE" strategy and recommendations.