It was with much interest I read the insightful and careful study by Lewallen and colleagues1 in which they used data from a number of population-based studies in Africa to assess what might be the appropriate cataract surgery rate (CSR). They show, not unexpectedly, that the CSR changes with the level of visual acuity used as an indicator for cataract surgery, whether one or both eyes are operated on, and the proportion of older people in the population.