Trachoma is the world’s leading cause of infectious blindness, an estimated 84 million people have active trachoma and 7.6 million have trachomatous trichiasis.¹ It is a disease of poor personal and community hygiene, affecting those living in the poorest conditions, and disappears as living conditions improve. Repeated or persistent infection with the obligate intracellular bacteria Chlamydia trachomatis results in the clinical syndrome of blinding trachoma. Trachoma progresses from inflammation of the upper tarsal conjunctiva to scarring; distortion of the eyelid causes trichiasis and eventual loss of vision secondary to corneal opacity after which blindness is essentially irreversible. The SAFE strategy developed by the World Health Organization (WHO) is effective in controlling blinding trachoma.² It targets trachoma intervention at various stages of the cycle of disease: Surgery for trichiasis, Antibiotics for active trachoma, Facial cleanliness, and Environmental improvements. However, simple, reliable, and cost effective systems are needed to identify populations at risk of the blinding complications of trachoma and to assess the effectiveness of trachoma intervention programmes.

METHODS TO ESTIMATE TRACHOMA PREVALENCE

Population based prevalence surveys are the gold standard for estimating the prevalence of active trachoma and trachomatous trichiasis within a community. They have proved the mainstay of targeting and monitoring trachoma intervention; however, they are expensive, time consuming and may utilise …