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Open AccessArticle
Spherical Equivalent Percentile Curves in a Portuguese School-Aged Population
1
School for Doctoral Studies and Research, Universidad Europea de Madrid, 28670 Madrid, Spain
2
Instituto Superior de Educação e Ciências de Lisboa (ISEC Lisboa), Alameda das Linhas de Torres, 179, 1750-142 Lisboa, Portugal
3
Department of Veterinary Medicine, Universidad Europea de Madrid. Faculty of Biomedical and Health Sciences, 28670 Madrid, Spain
4
Department of Optometry and Vision, Faculty of Optics and Optometry, Universidad Complutense de Madrid, 28037 Madrid, Spain
*
Author to whom correspondence should be addressed.
J. Clin. Med. 2025, 14(20), 7262; https://doi.org/10.3390/jcm14207262 (registering DOI)
Submission received: 10 September 2025
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Revised: 8 October 2025
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Accepted: 10 October 2025
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Published: 14 October 2025
Abstract
Bacground/Objectives: This study aimed to develop age- and sex-specific spherical equivalent (SE) percentile curves and estimate the prevalence of refractive errors (REs) in Portuguese schoolchildren aged 6–17 years. Methods: A cross-sectional study was conducted in three schools in Lisbon, including 2205 children (mean age = 9.3 ± 2.6 years; 49.3% boys). Vision was assessed using non-cycloplegic static retinoscopy (chosen due to feasibility in school settings) and visual acuity tests. SE percentile curves (P5–P95) were generated by age and sex. SE values and RE distribution (hyperopia, emmetropia, and myopia) were compared across four age groups (6–8, 9–11, 12–14, and 15–17 years). Results: SE values decreased significantly with age (p < 0.001). Median SE ranged from +0.50 D (6–8 years) to 0.00 D (15–17 years), with no sex differences. Hyperopia predominated in younger children (60.6% at 6–8 years), whereas myopia increased in older ages (32.2% at 15–17 years). Conclusions: This study presents the first SE percentile curves for Portuguese schoolchildren, providing a practical, age-specific reference for vision screening. The progressive shift from hyperopia to myopia highlights the importance of early detection and monitoring to prevent visual impairment.
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MDPI and ACS Style
Peñaloza-Barbosa, M.I.; Martinez-Perez, C.; Andreu-Vázquez, C.; Sánchez-Tena, M.Á.; Alvarez-Peregrina, C.
Spherical Equivalent Percentile Curves in a Portuguese School-Aged Population. J. Clin. Med. 2025, 14, 7262.
https://doi.org/10.3390/jcm14207262
AMA Style
Peñaloza-Barbosa MI, Martinez-Perez C, Andreu-Vázquez C, Sánchez-Tena MÁ, Alvarez-Peregrina C.
Spherical Equivalent Percentile Curves in a Portuguese School-Aged Population. Journal of Clinical Medicine. 2025; 14(20):7262.
https://doi.org/10.3390/jcm14207262
Chicago/Turabian Style
Peñaloza-Barbosa, María Ibeth, Clara Martinez-Perez, Cristina Andreu-Vázquez, Miguel Ángel Sánchez-Tena, and Cristina Alvarez-Peregrina.
2025. "Spherical Equivalent Percentile Curves in a Portuguese School-Aged Population" Journal of Clinical Medicine 14, no. 20: 7262.
https://doi.org/10.3390/jcm14207262
APA Style
Peñaloza-Barbosa, M. I., Martinez-Perez, C., Andreu-Vázquez, C., Sánchez-Tena, M. Á., & Alvarez-Peregrina, C.
(2025). Spherical Equivalent Percentile Curves in a Portuguese School-Aged Population. Journal of Clinical Medicine, 14(20), 7262.
https://doi.org/10.3390/jcm14207262
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