“…3,6,7,[23][24][25] Observed rates of wear were low, ranging from 13% to 41%. 3,6,7,21,23,24 All of the few studies reporting higher rates (46% by Keay and associates in China, 25 56% by Vincent and associates in Thai refugee camps, 22 and 58% by von-Bischhoffshaussen and associates in Chile 20 ) relied on self-report and/or estimates of teachers or parents, 20,22 and had low (58%-76%) rates of follow-up 20,22 or assessment times as short as 1 month after spectacle distribution. 25 It would appear that longer-term (over the course of a school year) compliance with free spectacles, as measured by objective indicators such as observed wear at unannounced examinations, is low among children without additional interventions.…”