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. 2015 Oct-Dec;10(4):408-16.
doi: 10.4103/2008-322X.176909.

Prevalence of Amblyopia and Refractive Errors Among Primary School Children

Zhale Rajavi  1 , Hamideh Sabbaghi  2 , Ahmad Shojaei Baghini  3 , Mehdi Yaseri  4 , Hamidreza Moein  5 , Shadi Akbarian  5 , Narges Behradfar  5 , Simin Hosseini  5 , Hossein Mohammad Rabei  6 , Kourosh Sheibani  3
Affiliations

Prevalence of Amblyopia and Refractive Errors Among Primary School Children

Zhale Rajavi et al. J Ophthalmic Vis Res. 2015 Oct-Dec.

Abstract

Purpose: To determine the prevalence of amblyopia and refractive errors among 7 to 12-year-old primary school children in Tehran, Iran.

Methods: This population-based cross-sectional study included 2,410 randomly selected students. Visual acuity was tested using an E-chart on Yang vision tester. Refractive errors were measured by photorefractometry and cycloautorefraction. Strabismus was checked using cover test. Direct ophthalmoscopy was used to assess the anterior segment, lens opacities, red reflex and fundus. Functional amblyopia was defined as best corrected visual acuity ≤20/40 in one or both eyes with no anatomical problems.

Results: Amblyopia was present in 2.3% (95% CI: 1.8% to 2.9%) of participants with no difference between the genders. Amblyopic subjects were significantly younger than non-amblyopic children (P=0.004). Overall, 15.9% of hyperopic and 5.9% of myopic cases had amblyopia. The prevalence of hyperopia ≥+2.00D, myopia ≤-0.50D, astigmatism ≥0.75D, and anisometropia (≥1.00D) was 3.5%, 4.9%, 22.6%, and 3.9%, respectively. With increasing age, the prevalence of myopia increased (P<0.001), that of hyperopia decreased (P=0.007), but astigmatism showed no change. Strabismus was found in 2.3% of cases. Strabismus (OR=17.9) and refractive errors, especially anisometropia (OR=12.87) and hyperopia (OR=11.87), were important amblyogenic risk factors.

Conclusion: The high prevalence of amblyopia in our subjects in comparison to developed countries reveals the necessity of timely and sensitive screening methods. Due to the high prevalence of amblyopia among children with refractive errors, particularly high hyperopia and anisometropia, provision of glasses should be specifically attended by parents and supported by the Ministry of Health and insurance organizations.

Keywords: Amblyopia; Iran; Primary School; Refractive Error; Strabismus.

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Conflict of interest statement

Conflict of Interest: None declared.

Figures

Figure 1
Figure 1
Flowchart of the study. VA, visual acuity; PH, pinhole; BCVA, best corrected visual acuity; n, number.
Figure 2
Figure 2
Amblyopia prevalence according to age and sex of children.
Figure 3
Figure 3
Amblyopia prevalence in different refractive errors and anisometropia. H, hyperopia; M, myopia; Cyl, cylinder; A, anisometropia; SE, spherical equivalent; diff, difference; D, diopter.
Figure 4
Figure 4
Refractive error prevalence according to age and sex of students' eyes. SE, spherical equivalent; Cyl, cylinder; D, diopter.
See this image and copyright information in PMC

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