title: Changes in Myopia Prevalence among First-Year University Students in 12 Years.
abstract: The aim of this study is to compare the changes in myopia prevalence among Portuguese first-year university students in 2002 and 2014 at the University of Minho.
  
  
  
  The refractive status and axial length of first-year students at the School of Sciences, University of Minho, were measured in 2014. Refractive error was measured with subjective refraction under cycloplegia and axial length was measured by optical biometry. The data were compared with those obtained from a similar cohort of 111 students in 2002. Myopia was defined as a mean spherical equivalent of ≤-0.50D. A survey was conducted to know the routine of the participants. They were asked how many hours per week (hrs/wk) they had spent, on average in the previous year, watching TV, using the computer, studying, participating in manual hobbies, and participating in outdoor activities.
  
  
  
  In 2014, 75 students were assessed (15 male and 60 female) with a mean age (mean ± SD) of 19.8 ± 1.6 years (ranging from 18 to 24 years). The mean refractive error M (spherical equivalent) was -0.77 ± 1.79D and the axial length was 23.74 ± 1.19 mm. The prevalence of myopia was 41.3% (31 of 75). In 2002, the mean refractive error M was 0.01 ± 1.53D, the axial length was 23.40 ± 0.93 mm, and the myopia prevalence was 23.4% (26 of 111). The differences between myopia prevalence and mean refractive error are statistically significant (p < 0.05). A statistically significant increase in the number of hrs/wk spent on near activities (p < 0.05) was found.
  
  
  
  In 12 years, the prevalence of myopia among first-year university students at the School of Sciences of the University of Minho rose from 23.4 to 41.3%. This increase in myopia prevalence could be related to the lifestyle changes of the studied population.
authors.affiliation: *PhD †MSc Clinical and Experimental Optometry Research Laboratory (CEORLab), Center of Physics (Optometry), School of Sciences, University of Minho, Braga, Portugal (all authors).
authors.forename: Jorge
authors.initials: J
authors.lastname: Jorge
authors.forename: Ana
authors.initials: A
authors.lastname: Braga
authors.forename: António
authors.initials: A
authors.lastname: Queirós
mesh_terms: D000293:Adolescent; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009216:Myopia / Q000175:diagnosis / Q000453:epidemiology*; D011174:Portugal / Q000453:epidemiology; D015995:Prevalence; D012029:Refraction, Ocular / Q000502:physiology; D013334:Students / Q000706:statistics & numerical data*; D011795:Surveys and Questionnaires; D014495:Universities; D055815:Young Adult