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Clinical Relevance: Information on the refractive error prevalence in school-aged children will result in delivering the optimal eye health service to this group., Background: Understanding the prevalence of refractive error in school-aged children is crucial to reduce the consequences of uncorrected refractive error. This study aims to investigate the prevalence of refractive error among school-aged children in Shiraz, Iran., Methods: In this cross-sectional population-based study, 2001 schoolchildren aged 6-12 years participated. All participants underwent cycloplegic refraction. Spherical equivalent (SE) of -0.50 dioptre or more was considered as myopia, SE of +2.00 dioptre or more as hyperopia, and astigmatism as cylinder power of 0.75 dioptre or more. The difference of 1.00 dioptre or more between two eyes defined as anisometropia., Results: The prevalence of myopia was 11.6% (95% confidence interval [CI]: 10.2-13.1%), hyperopia 6.7% (95%CI: 5.6-7.9%), and astigmatism 28.9% (95%CI: 26.9-31.0%), out of which 82.1% had with the rule astigmatism. Anisometropia was detected in 4.0% (95%CI: 3.2-5.0%) of children. Astigmatism and anisometropia were significantly higher in boys ( p < 0.001, p = 0.03 respectively). The SE decreased significantly with increasing age ( p < 0.001) indicating an increase in myopia with age. In addition, the rate of myopic astigmatism increased with age ( p < 0.001). Among studied schoolchildren 97.0% could achieve the best-corrected visual acuity of 6/6 and 3.0% could not in the better eye., Conclusion: Astigmatism was the most common refractive error among primary school children. The prevalence of myopia was relatively higher than other studies conducted in Iran, and it increased with age. These results may highlight the role of lifestyle changes and increased near work activities on the myopic shift in school-aged children. The findings provide information for screening programmes in school-aged children.

Background: The aim of this study was to evaluate the prevalence of anisometropia in an urban adult population in the north of Iran., Methods: This cross-sectional study was conducted among the 40-64-year-old population in Shahroud, Iran. Random cluster sampling was applied to select 6,311 people. Following an interview, optometric and ophthalmologic examinations, including objective non-cycloplegic refractions, were carried out. The prevalence of anisometropia was reported according to non-cycloplegic refraction and with cut-off points of 0.50, 1.00, 2.00 and 3.00 D., Results: Of the sampled people, 5,190 (82.2 per cent) took part in the study. After considering exclusion criteria, data from 4,918 participants were included in the final analysis. Most participants were female (57.6 per cent) and the average age (with standard deviation) was 50.7 ± 6.2 years. The prevalence of anisometropia with cut-off points of 0.50, 1.00 and 2.00 D were 23.1 (95%CI: 22.0-24.3), 7.7 (95%CI: 7.0-8.4) and 3.2 per cent (95%CI: 2.7-3.7), respectively. The prevalence of severe anisometropia (3.00 D or more) was 1.9 per cent (95%CI: 1.5-2.3). The odds ratio (OR) of anisometropia was 1.06 times higher for every year of increasing age. The OR of anisometropia in participants with cataract was 2.78 times more than in those without (p < 0.001). Anisometropia was more frequent among participants with unilateral cataract (21.7 per cent) compared to those with bilateral cataract (13.4 per cent). Anisometropia of 1.00 D or more was significantly more prevalent among myopic participants compared to hyperopic participants (13.8 versus 12.7 per cent, p < 0.001) and there was a stronger association between anisometropia and myopia (OR = 2.93) than hyperopia (OR = 2.23). With increasing educational level, the prevalence of anisometropia decreased significantly (p < 0.001). The prevalence of aniso-astigmatism of 1.00 D or more was 11.1 per cent (95%CI: 10.2-11.9)., Conclusion: In the present study, the prevalence of anisometropia in Iran was not negligible; however, it is less than in Eastern Asia. Myopia, cataract, age and educational level were associated with anisometropia., (© 2013 The Authors. Clinical and Experimental Optometry © 2013 Optometrists Association Australia.)