Prevalence of refractive error within a Portuguese sample of optometric records

Purpose: Considering the burden of refractive error, clinical-based research methods are often used as epidemiological tools. This study aimed to generate evidence on the prevalence and distribution of refractive error in Portugal. Methods: A cross-sectional retrospective study was designed to review optometric records from Portuguese practices during July 2021. Results: 348 optometric records were analysed. Subjects had a mean age of 44.2 +/- 19.2 years (range 6-81) and 58.4% were female. The mean spherical equivalent was myopic,-0.65 +/- 2.38 Diopters (D), varying from a minimum of-13.63 to a maximum of 6.25 D. According to sex, the mean spherical equivalent was-0.76 +/- 2.29 D for female and-0.49 +/- 2.49 D for male, with no significant difference between them (p = .307). The distribution of the spherical equivalent mean across the age groups, linearly varies from a myopic-1.62 +/- 1.74 D in the age group of [6 29];-1.58 +/- 2.80 Din [30 44];-0.09 +/- 2.40 in [45 59] to a hyperopic 0.67 +/- 1.61 Din the group of [60 81]. High myopia had a prevalence of 2.7% in the sample. Myopia was the most prevalent refractive error in the sample representing 41.3%. In the age group [6-29], myopia had a prevalence of 69.3%. Hyperopia had a prevalence in the sample of 29.7%. Conclusions: Myopia represents the most prevalent refractive error within the sample and is the prevalence is higher in the younger age groups, demonstrating a shift towards an increase of myopia in the next years. (c) 2023 Spanish General Council of Optometry. Published by Elsevier Espana, S.L.U. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/bync-nd/4.0/).