Trachoma is the leading infectious cause of blindness worldwide and is caused by recurrent episodes of infection with Chlamydia trachomatis. Repeat infection is characterized by inflammatory changes in the conjunctiva in children with subsequent scarring, corneal opacity, and blindness in adults. It is largely found in poor, rural areas in low-income countries. Trachoma is an ancient disease and there have been concerted efforts more recently to eliminate blindness from trachoma.
From as early as the twenty-seventh century BC in China there have been references to trachoma.1 The Ebers papyrus from Egypt, fifteenth-century BC, also makes reference to trachoma and epilation forceps have been discovered in tombs from the nineteenth-century BC.2,3 At the beginning of the nineteenth-century trachoma became a major public health problem in Europe when the disease was believed to have been brought back by troops returning from the Napoleonic wars in Egypt. Many of the major ophthalmic hospitals founded in the nineteenth century were established to treat trachoma, including Moorfields Eye Hospital and Massachusetts Eye and Ear Infirmary. Immigrants to the United States were routinely screened for trachoma at the end of the nineteenth century and sent home if they had signs of the disease. Trachoma has now disappeared from developed countries (with the exception of Aboriginal communities in outback Australia), probably as a result of general improvements in living and hygiene standards.4
Blinding trachoma is endemic in at least 20 countries, largely in poor and remote areas across Africa, Asia, Latin America, the Middle East, and the Pacific rim.5,6 In 2016, there were an estimated 190 million people living in regions requiring trachoma control programs, 3.1 million who require surgery for trichiasis, and 1.9 million who are blind or have significant visual impairment from trachoma.5–8 The vast majority of these people live in the African region.
Some caution needs to be applied when interpreting trachoma prevalence estimates as various assumptions and extrapolations are used, and there is a relative lack of data from India and China. Small changes in the prevalence of either of these countries potentially has a large effect overall. However, it is clear that the numbers estimated to be affected by trachoma have shown large reductions in recent decades and the number of countries that are thought to have eliminated trachoma (at least the active form) is increasing. This is likely a result in part of trachoma control strategies, but also general improvements in living and hygienic standards.
Loss of vision and ocular pain from trachoma leads to loss of economic productivity and quality of life, with the burden of disease estimated to be around 1.3 million disability-adjusted life years (DALY) in 2004, although this is likely to be an underestimation.9–11 Trachoma tends to be found in remote, rural areas, is strongly associated with ...