Visual impairment and blindness in a population-based study of Mashhad, Iran

Hashemi, H. and Khabazkhoob, M. and Saatchi, M. and Ostadimoghaddam, H. and Yekta, A. (2018) Visual impairment and blindness in a population-based study of Mashhad, Iran. Journal of Current Ophthalmology, 30 (2). pp. 161-168.

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Purpose: To determine the prevalence of visual impairment and blindness and related factors in the 1- to 90-year-old urban population of Mashhad. Methods: In this cross-sectional study of 1- to 90-year-old residents of Mashhad, in northeastern Iran, sampling was done through random stratified cluster sampling (120 clusters). After selecting the samples and their participation in the study, all subjects had vision testing including measurement of visual acuity and refraction, as well as examinations with the slit-lamp and ophthalmoscopy. Visual impairment (primary outcomes) was defined as a visual acuity worse than of 0.5 logMAR (20/60) in the better eye. Results: Of the 4453 selected persons, 3132 (70.4) participated in the study. The prevalence of visual impairment based on presenting vision and best-corrected vision was 3.95 (95 confidence interval CI: 3.13–4.77) and 2.23 (95% CI: 1.54–2.91), respectively. The prevalence of presenting visual impairment increased from 1.59% in children under 5 years of age to 43.59% in people older than 65 years of age; these figures were respectively 1.59% and 42.31% based on corrected visual acuity. In the logistic regression model, older age (OR = 1.06, 95% CI: 1.04–1.07, P < 0.001), higher education (OR = 0.16, 95% CI: 0.06–0.38, P < 0.001), and low income (OR = 1.36, 95% CI: 1.21–1.72, P < 0.001) correlated with impaired sight. Based on presenting vision and best-corrected vision, the prevalence of blindness was 0.86% (95% CI: 0.51–1.22) and 0.32% (95% CI: 0.1–0.55). The most common causes of visual impairment were uncorrected refractive error (41.8%) and cataract (20%). Conclusions: According to our findings, the prevalence of visual impairment was intermediate in comparison with other studies. The prevalence of visual impairment in our study was similar to the global average; however, it was markedly high at older ages. Nonetheless, refractive errors and cataracts remain as the main causes of impaired vision and blindness in this population, while these two conditions are easily treatable with correction or surgery. © 2018 Iranian Society of Ophthalmology

Item Type: Article
Additional Information: Cited By :3 Export Date: 16 February 2020 Correspondence Address: Ostadimoghaddam, H.; Refractive Errors Research Center, School of Paramedical Sciences, Mashhad University of Medical SciencesIran; email:
Uncontrolled Keywords: Blindness Cross-sectional study Low-vision Middle-East Visual impairment adolescent adult age aged Article best corrected visual acuity child educational status eye refraction female human income Iran major clinical study male middle aged ophthalmoscopy population research preschool child prevalence refraction error urban population very elderly vision test visual acuity
Subjects: WW Ophthalmology
Divisions: Mashhad University of Medical Sciences
Depositing User: lib2 lib2 lib2
Date Deposited: 20 May 2020 03:47
Last Modified: 20 May 2020 03:47

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