In Reply

We thank Dr. Barry for his interest in our article (1). We agree that the approach of the KiGGS study by the Robert Koch Institute to ascertain refractive errors by self-disclosure has its methodological limits. We have also explained this in detail in the section on the study limitations. For example, we would have liked to conduct the above-mentioned validation of the parents’ information using refraction measurements to determine the error rate. Unfortunately, this was not possible, as it was not provided for in the data collection (which had already been completed). However, we observed that parents were somewhat more likely to give no information about their child’s refractive errors in the 2003–2006 baseline survey than in the 2014–2017 follow-up survey; this observation is mentioned in the results of our article. Overall, our results are consistent with studies of Caucasian children in other countries. A meta-analysis showed that the prevalence of myopia in white European children has either a marginal decline or is stable (2), which is why we consider our result to be plausible.

We support the recommendation of 1 to 2 hours of daylight exposure per day in childhood. This has been shown to be preventative for the development and progression of myopia (3) and should be integrated into everyday life. A recent study in China also showed that the lockdown, with strict stay-at-home orders, led to a higher proportion of myopic children aged 6 to 8 years (4), underscoring the importance of being outdoors and showing the first possible consequences of lockdowns on the development of myopia. We fully agree with the statement that development of motor, social, and cognitive skills are additionally promoted by being outdoors. Sufficient information about limiting screen time and the necessity of being outdoors will only be possible through the interdisciplinary cooperation of ophthalmologists and pediatricians and should be scientifically evaluated.