Hassan Hashemi1, Amir Asharlous2, Mehdi Khabazkhoob3, Abbasali Yekta4, Mohammad Hassan Emamian5, Akbar Fotouhi6. 1. Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran. 2. Rehabilitation Research Center, Department of Optometry, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran. 3. Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 4. Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran. 5. Ophthalmic Epidemiology Research Center, Shahroud University of Medical Sciences, Shahroud, Iran. Electronic address: emamian@shmu.ac.ir. 6. Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
Abstract
PURPOSE: To determine the prevalence of astigmatism and its determinants in schoolchildren aged 6-12 years. METHODS: The students selected by stratified cluster random sampling in Shahroud, north of Iran. Optometric examination included uncorrected visual acuity, refraction with autorefractometer, manifest refraction with retinoscopy followed by subjective and cycloplegic refraction (after two drops of cyclopentolate 1% with 5min interval were instilled in each eye). A cylinder power ≥0.75diopter (D) in at least one eye was considered as astigmatism. The prevalence of astigmatism was reported based on a cylinder power higher than 0.50, 1.00, and 2.00D in cycloplegic refraction, followed by power vector analysis. RESULTS: After applying the inclusion criteria, the data of 5528 children were analyzed. The prevalence of astigmatism was 16.7% (95% CI: 15.6-17.7) in total, 16.6% (95% CI: 15.2-18.0) in boys and 16.8% (95% CI: 15.2-18.3) in girls (p=0.920) and decreased from 21.5% in 6-year-old children to 13.7% in 10-year-olds, and then again increased to 18.3% in children aged 12 years. Moreover, 17.2% (95% CI: 16.0-18.3) of urban and 12.1% (95% CI: 10.0-14.1) of rural children had astigmatism (p<0.001). The prevalence of with-the-rule, against-the-rule, and oblique astigmatism was 14.2%, 2.1%, and 0.33%, respectively. The mean cylinder power was -1.31, -0.46, and -0.44D in children with spherical myopia, emmetropia, and hyperopia, respectively (p<0.001). Urban students had a higher J0 and boys had a higher J45. CONCLUSION: The prevalence of astigmatism in this study was lower than previous studies. Astigmatism prevalence was markedly higher in urban children.
PURPOSE: To determine the prevalence of astigmatism and its determinants in schoolchildren aged 6-12 years. METHODS: The students selected by stratified cluster random sampling in Shahroud, north of Iran. Optometric examination included uncorrected visual acuity, refraction with autorefractometer, manifest refraction with retinoscopy followed by subjective and cycloplegic refraction (after two drops of cyclopentolate 1% with 5min interval were instilled in each eye). A cylinder power ≥0.75diopter (D) in at least one eye was considered as astigmatism. The prevalence of astigmatism was reported based on a cylinder power higher than 0.50, 1.00, and 2.00D in cycloplegic refraction, followed by power vector analysis. RESULTS: After applying the inclusion criteria, the data of 5528 children were analyzed. The prevalence of astigmatism was 16.7% (95% CI: 15.6-17.7) in total, 16.6% (95% CI: 15.2-18.0) in boys and 16.8% (95% CI: 15.2-18.3) in girls (p=0.920) and decreased from 21.5% in 6-year-old children to 13.7% in 10-year-olds, and then again increased to 18.3% in children aged 12 years. Moreover, 17.2% (95% CI: 16.0-18.3) of urban and 12.1% (95% CI: 10.0-14.1) of rural children had astigmatism (p<0.001). The prevalence of with-the-rule, against-the-rule, and oblique astigmatism was 14.2%, 2.1%, and 0.33%, respectively. The mean cylinder power was -1.31, -0.46, and -0.44D in children with spherical myopia, emmetropia, and hyperopia, respectively (p<0.001). Urban students had a higher J0 and boys had a higher J45. CONCLUSION: The prevalence of astigmatism in this study was lower than previous studies. Astigmatism prevalence was markedly higher in urban children.