The prevalence of convergence insufficiency in Iran: a population-based study

Hashemi, H. and Nabovati, P. and Khabazkhoob, M. and Ostadimoghaddam, H. and Doostdar, A. and Shiralivand, E. and Yekta, A. (2017) The prevalence of convergence insufficiency in Iran: a population-based study. Clinical and Experimental Optometry, 100 (6). pp. 704-709.

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Purpose: The aim was to determine the prevalence of convergence insufficiency and its relationship with age, gender and refractive error in a population-based study. Methods: In this cross-sectional study, all residents over one year old in Mashhad city, in the north east of Iran, were sampled through random stratified cluster sampling. After selecting samples and their participation in the study, they all had eye examinations including the measurement of visual acuity, refraction, binocular vision assessment, including cover test, measurement of near point of convergence and fusional vergences and finally, slitlamp biomicroscopy. Results: Of the 4,453 selected people, 3,132 participated in the study and finally, analyses were done with data from 2,219 individuals. The mean age of the participants was 30.5 ± 14.0 years (range: 10 to 69). The prevalence of convergence insufficiency in this study was 5.51 per cent (range: 4.51 to 6.52): 4.78 per cent (range: 3.11 to 6.45) in males and 5.86 per cent (range: 4.60 to 7.11) in females (p = 0.276). Convergence insufficiency prevalence in different age groups showed no significant linear trend; however, a significant increase was observed after the age of 60 years. The prevalence of myopia, emmetropia and hyperopia was respectively 12.1, 56.9 and 31 per cent in participants with convergence insufficiency and 15.9, 54.4 and 29.6 per cent in those without convergence insufficiency (p = 0.537). Multiple logistic regression models revealed no significant relationship between the prevalence of convergence insufficiency and age, gender or refractive errors. Conclusion: This study showed that the overall prevalence of convergence insufficiency in the Iranian population was 5.46 per cent, which is lower than that in the majority of previous studies. Convergence insufficiency prevalence had no significant change with age up to the age of 60 years but increased significantly after 60 years. © 2017 Optometry Australia

Item Type: Article
Additional Information: Cited By :7 Export Date: 16 February 2020 CODEN: CEOPE Correspondence Address: Ostadimoghaddam, H.; Refractive Errors Research Center, School of Paramedical Sciences, Mashhad University of Medical SciencesIran; email:
Uncontrolled Keywords: age convergence insufficiency gender population-based prevalence refractive errors adolescent adult age distribution aged child cross-sectional study eye movement disorder female human Iran male middle aged refraction error sex ratio slit lamp very elderly young adult Aged, 80 and over Cross-Sectional Studies Humans Ocular Motility Disorders Sex Distribution
Subjects: WW Ophthalmology
Divisions: Mashhad University of Medical Sciences
Depositing User: mr lib3 lib3
Date Deposited: 28 Apr 2020 08:52
Last Modified: 28 Apr 2020 08:52

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