Introduction and objectives: Refractive errors in childhood and adolescent age have increased significantly in the last few decades, and in some world regions, especially East Asia, they have escalated to the level of epidemic. The aim of this work was to explore the correlation between physical activity and the occurrence of refractive errors among school-age children. The research was carried out in 13 elementary schools in Zagreb among eighth grade pupils, in the city districts of Trnje, Trešnjevka Jug, Trešnjevka Sjever and Peščenica-Ţitnjak. Participants and methods: A total of 165 eighth grade elementary school pupils (57% of girls) and their parents participated in the research. The pupils and parents estimated the time that pupils spend learning, working on the computer, looking at the mobile phone, watching television, doing sports, practising leisure activities, taking walks, and spending time outdoors and indoors. The data obtained through the questionnaire were compared to the eyesight examination reports collected during preventive health examinations in school health centres during school year 2016/2017. In the data analysis, for each of the questions in which the duration of a particular activity was estimated, an average value of pupils’ and parents’ time estimation was used. Results: Pupils with normal eyesight spend significantly more time in front of the screen (computer, mobile phone and television) and outdoors, in comparison to pupils with eyesight errors. A total of 64.82% of pupils with normal eyesight, and 24.56% of pupils with eyesight errors spend more than 150 minutes a day in front of the screen. More than a half of pupils with normal eyesight and a little more than a third of pupils with eyesight errors spend more than 120 minutes a day outdoors. There was no statistically significant difference regarding the time spent doing sports and the presence of refractive errors in parents found between pupils with normal eyesight and pupils with eyesight errors. There was no statistically significant correlation between the time spent learning and doing homework and the occurrence of eyesight errors among pupils. Conclusion: The results of this research can be used in planning preventive health measures that would encourage children to spend more time outdoors during classes and outside of school hours.