Screening of Primary School Children for Amblyopia and Amblyogenic Factors in Central Cairo, Egypt

Abstract

Objective To measure the prevalence of amblyopia and amblyogenic factors among primary school children and to evaluate distance visual acuity (VA) as a screening test to detect amblyopia and define its cutoff value. Subjects and Methods A cross-sectional study was conducted on primary school children in two schools in Central Cairo. Children underwent assessment of visual acuity using Landolt broken ring. Comprehensive ophthalmologic examination was performed for amblyopia suspects at the Ophthalmology Department of Ain Shams University Hospitals, including reassessment of best-corrected visual acuity (BCVA) using the same chart. Results A total of 352 children were examined. Reduced screening VA (amblyopia suspect) was detected in 47 subjects (13.35%) proved amblyopia after comprehensive examination was 1.98% (7 cases). Refractive errors (REs) were present in all suspected and proved amblyopia cases (100%) but was only present in 11.6% of nonamblyopic students (P < 0.05). The prevalence of hyperopia in the whole sample was 3.6%, and was 27.6% in subjects with RE. Thirty percent of hyperopic eyes were amblyopic. The prevalence of myopia was 9.3% of the whole sample and 70% of students with RE. Only 9% of myopic eyes were amblyopic. Mild to moderate amblyopia (VA better than 0.2log MAR) was 42.9%, while severe amblyopia represented 57.1%. Conclusion This study emphasizes the importance of school-based eye care system targeting the detection of amblyopia by application of a fast screening distance VA test with a cutoff value of high sensitivity at log MAR 0.539 (Snellen′s VA equivalent 6/18).

Prevalence of Amblyopia in 2018

“…The prevalence of amblyopia was found to be highest among European and lowest among African populations as depicted by Hashemi et al [3]. Our results agree with Hashemi et al's in respect to African population as shown by the Egyptian report of a rate of 1.98%, very consistent with the world-wide rate of 1.75% [4], however not one of the lowest. Denmark [5], Saudi Arabia [6], China [7], Romania [8], Bulgaria [9], Israel [10] and Brazil [11] reported rates ranging around the average rate worldwide.…”

Screening of refractive error among primary school students at Tanta City Gharbia governorate Egypt. How serious is the problem?

“…10 On the other hand our finding was higher than Rashad MA et al (2018) in Cairo as 13.4% out of 352 school students aged 8-12 years had RE. 4 Also, lower figure was reported by Vidusha KS (2018) in India, as the prevalence rate was 10.5% in a study included 1140 school children aged 7-16. 11 This difference in finding may be due to different study design, sample size and/or age of students included in the study.…”

“…This disagrees with other Egyptian studies that reported myopia as most common followed by hyperopia and lastly astigmatism (70.2%, 27.6%, and 25.5% respectively). 4 Another study in India reported myopia followed by astigmatism and lastly hyperopia (58.5%, 24.4%, and 17.1% respectively). 11 On the other hand, our finding agrees with Hashemi H (2017) finding in systematic review and meta-analysis that astigmatism was the most common refractive error in children.…”

“…Suspected amblyopia cases that referred for further investigation in University Hospital were 31.1% of RE students (6.9% of all students), this was much higher than those reported in Cairo (2018) of 13.4% suspected amblyopic children out of all examined primary school children. 4 This different figure which more evident in governmental school may be due to the higher percent of undiscovered RE in them (81.7% of RE governmental student did not wear glasses). This raises the importance of implementation and good monitoring of the school RE screening program to avoid the occurrence of amblyopia.…”

“…3 Many studies carried out in Egypt revealed that the prevalence of refractive errors in school children ranged from 13.4% to 39%. 4,5 Also, other studies showed that refractive error was responsible for 1.1% legal blindness (which is defined as vision less than 6/60). 6 Refractive errors can be easily detected and corrected by the use of glasses saving many years of blindness, this motivated us to carry out the present study.…”