Strengths and limitations
DIMS, A major weakness
REFRACTIVE ERROR, MYOPIA
Most studies of atropine and all trials of DIMS have been on Asian populations and this study is an important extension of this work to a European population. Another strength of the study is the novel inclusion of a combined atropine+DIMS group.A major weakness is that participants chose which intervention they received: there was no random allocation to groups. The clinic in which participants were examined had a reputation for myopia control with atropine and therefore more participants elected to be in this group. Although random allocation to groups is desirable to reduce the risk of bias, it has the disadvantage of making results less relevant to clinical practice. This is one reason why it has been argued that hierarchies of evidence should be replaced by an acceptance of the need for a diversity of approaches, including non-randomised observational studies [Another limitation is that the study was single-masked, and participants were not masked to the treatment they received. In mitigation, it is helpful that the measurements of refractive error and AL were objective and taken by clinicians who were masked to the treatment that each participant was receiving. The method of measuring VA is suboptimal (whole line scoring and test ceiling of 1.0 decimal (0.0 LogMAR)).The duration of the study of one year is similar to some other research in this field [The study population represent individuals and families who are motivated to pursue myopia control and were attending a clinic that built a strong rapport with patients, which no doubt contributed to the high compliance rate. It is not known whether the findings will apply to less motivated populations. Similarly, it is not known whether the novel findings concerning combined atropine+DIMS apply to populations with other racial origins.