Estimation of global visual impairment due to uncorrected refractive error

The paper by Resnikoff et al.1 on the global magnitude of visual impairment caused by uncorrected refractive error published in the Bulletin of the World Health Organization in January 2008 does not refer to our previous publication2 on the same topic in BMC Medicine that precedes their paper by about two years and is readily available in the public domain. The reason for this is unclear as our paper clearly shows up in a PubMed® search for both “blindness” and “visual impairment”. In addition, the global estimates of blindness and visual impairment due to uncorrected refractive error made in our paper are know to the blindness community as they were presented at the World Ophthalmology Congress at Sao Paulo in February 2006. It is therefore surprising that Resnikoff et al. did not follow the usual norm of referring to previously published relevant literature. While there are differences in the inclusion criteria for studies in our paper and that of Resnikoff et al., with our paper using stricter criteria leading to fewer qualifying studies, and there were differences in the estimates of blindness and visual impairment due to uncorrected refractive error in the two papers, these should not be reasons for not referring to previously published work.