The Impact of Parental Rural-to-urban Migration on Children?s Refractive Error in Rural China: A Propensity Score Matching Analysis

Purpose: Parental rural-to-urban migration has a wide range of health effects on children?s but its impact on children?s refractive status remains unclear. We aim to examine whether parental rural-to-urban migration could influence the refractive status of their children in rural areas of China. Methods: Among the 2346 grade 7 students in the Mojiang Myopia Progression Study, information regarding parental migration was collected by questionnaires and was successfully obtained in 2105 participants. Refractive error was measured in diopters (D) with cycloplegia using an autorefractor and axial length (AL) was measured using an IOL Master. One-to-one nearest-neighbor matching techniques with a 0.01 caliper level were used to estimate the propensity score matching (PSM) models. Results: Among all the participants, 472 pairs (1 student with vs. 1 student without migrant parents) were successfully matched based on propensity scores. Students with migrant parents had a lower proportion of myopia (29.2% vs. 40.7%; P < .001) and more hyperopic refractions (?0.25D vs. ?0.31D; P = .04) compared with those without. They also had shorter ALs (23.4 mm vs. 23.6 mm) but the difference was not significance (P = .18). In addition, students with migrant parents spent less time reading after school per day (0.87 vs. 1.01 hours; P = .01). Conclusions: Myopia is less prevalent among children with migrant parents compared with those without. This study indicated that living without parents might be a protect factor for myopia in Chinese school student via giving them less pressure on study.