Estimates of the number of people worldwide with refractive error range from about 800 million to 2.3 billion.

In 1997, the World Health Organization set itself an ambitious goal to eliminate avoidable blindness in the world by 2020, with one of the five main priorities being refractive errors.1,2 A recent review of the impact of Vision 2020 on preventable blindness, other than uncorrected refractive errors, indicates that current estimates of global blindness are less than projected, and thus the trend is in the right direction to meet the Vision 2020 goal for the other conditions.3 The article by Fotouhi et al in this month’s issue of BJO (p 534) indicates that we are not doing so well on meeting the goal to eliminate vision impairment caused by uncorrected refractive error in Tehran. At this point, perhaps readers are thinking that the problem of uncorrected refractive error is unique to countries with relatively poorer healthcare systems. Let us consider the paper by Fotouhi et al in the global context of vision impairment caused by refractive errors.

Refractive errors (myopia, hyperopia and astigmatism; presbyopia is not included in this study given the present paucity of data, but it is recognized that uncorrected, it could lead to an impaired quality of life) affect a large proportion of the population worldwide, irrespective of age, sex and ethnic group. Such refractive errors can be easily diagnosed, measured and corrected with spectacles or other refractive corrections to attain normal vision. If, however, they are not corrected or the correction is inadequate, refractive errors become a major cause of low vision and even blindness (for a selection of studies, see http://ftp.who.int/nmh/references/RE-estimates-references.pdf).