Trachoma is known to be endemic in more than 50 countries and is responsible for the loss of an estimated 1.3 million disability-adjusted life years, with the majority of the global burden in sub-Saharan Africa. Visual impairment is the primary disabling sequelae of trachoma that informs global estimates of disability.
Approximately 1.3 million people are blind due to trachoma and an additional 1.8 million have low vision. However, trichiasis itself can cause excruciating pain and disability even before vision is affected.
Previous attempts to estimate numbers affected by trachoma and quantify associated disability have relied on the results of a limited number of surveys conducted in a few endemic countries. Extrapolation to wider geographic regions results in a high level of uncertainty around these estimates and associated parameters.
As additional survey data becomes available, and mapping techniques improve, it may be possible to improve this methodology and refine estimates of disease burden.