 Hello and welcome to week 4. Many of us probably never even give spectacle correction a second thought, and yet there are more than 100 million people around the world who are visually impaired because of a lack of spectacles. In this week we will look at what is required in order to detect and manage these refractive errors. Provision of refractive error services should ideally be within a health system, and yet it also has to be balanced with what is the acceptance by both the individual and the community. In this week, Professor Claire Gilbert shares her views on the models and the challenges of refractive error service provision and also on what it means to provide school vision testing.