Uncorrected refractive error barely features when it comes to reports of global visual impairment.¹ The reason is simple—the World Health Organization (WHO) definition² classifies visual impairment and blindness according to visual acuity with “best possible correction”. Recent population-based surveys have reported visual acuity in its many guises as uncorrected, presenting with habitual correction and best corrected. This work has exposed the enormous burden of uncorrected refractive error among industrialised^3,4 and developing nations.^5,6

The survey from Timor-Leste reported by Ramke et al⁷(see page 860) in this issue of the BJO represents an important addition to the literature. This population-based survey reports on uncorrected refractive error and presbyopia in adults (aged ⩾40 years) of Timor-Leste. This country is poverty stricken and has recently emerged as an independent democracy from a period of great upheaval. What is it about this survey that is of particular interest?

First, this is one of the few population-based surveys of refractive error that have reported on spectacle coverage for distance vision. We defined this term when reporting on spectacle coverage in the Bangladesh National Low Vision and Blindness Survey⁸ as Met refractive error need/(Met refractive error need+Unmet refractive error need)×100. The authors of the Timor-Leste study have used this definition and have explored the assumptions involved with it, for distance and near vision— a useful exercise for further studies that intend to assess coverage. Unsurprisingly, distance spectacle coverage was higher among the urban and literate and those in paid employment, compared with rural, illiterate and those adults involved in subsistence farming.

Second, this survey is unusual in …