What Counts as a Completed Correction?
Refractive-error care is best judged by what happens between a service encounter and a usable correction. This chapter connects the delivery routes and handoffs in that pathway to a practical endpoint ladder: reach, assessment, prescription, acquisition, wearing, sustained use, and benefit. The value of the ladder is simple: it lets a reader ask what a program result actually demonstrates before deciding that a visual need has been met.
One pathway, several endpoints
A service can be present in a school, travel through an outreach visit, or operate from a permanent centre. Those settings answer the question of where care begins. They do not, by themselves, answer what state the person reaches afterward. The same person can be counted as screened, assessed, prescribed spectacles, supplied with spectacles, and observed wearing them at different moments, while each count describes a different event.
The distinction is not pedantic. A school-based service may reach a child who would not visit a clinic. An outreach team may test a person in a remote community. A vision centre may provide a stable place for assessment and dispensing. But if the test result does not lead to assessment, if the prescription does not lead to acquisition, or if the spectacles are acquired but not worn, the later problem is not erased by the quality of the first contact.
The two reviews make this division visible from opposite directions. The Cochrane review describes how refractive and optical services are delivered in community and primary-care settings, including testing, assessment of the need for spectacles, and spectacle provision. The Frontiers review asks a narrower downstream question in children: when free spectacles are offered, how many children are compliant with wearing them, and what factors are associated with use? Neither review treats the entire pathway as one single outcome measured in the same people.
That means a program should not use one headline to stand in for every link. “We screened 10,000 children” says something about reach and an initial test. It does not say how many had a refractive need, how many received an assessment, or how many obtained spectacles. “We distributed 2,000 pairs” says more about provision, but it does not establish ownership in practice, wearing, or continued use. A wearing estimate is further downstream, yet it still depends on when and how wearing was measured.
The endpoint ladder is therefore not a ranking of outcomes in which every program must report the last one or be considered worthless. It is a way to align a claim with the question it answers. A service may be deliberately evaluating reach in a hard-to-access population. Another may be testing whether a financing change increases wearing. The error comes when a result at one level is silently promoted to a conclusion at another.
The endpoint ladder in practice
The first rung is reached. Someone comes into contact with the service through a school, outreach visit, pharmacy, health centre, vision centre, or another reported route. Reach matters because a service cannot help people it never encounters. It is also a property of the delivery system, not evidence that everyone reached has the same need or receives the same correction.
The second rung is assessed. A screening or vision test may identify a possible problem, but a refractive assessment determines whether spectacles are needed and what correction is appropriate.