Please use this identifier to cite or link to this item:
PIRA download icon_1.1View/Download Full Text
Title: Risk factors for myopia in 2 Hong Kong school systems : a pilot study
Authors: Liang, Y 
Kee, CS 
Issue Date: Jan-2022
Source: Asia-Pacific journal of ophthalmology, Jan.-Feb. 2022, v. 11, no. 1, p. 19-26
Abstract: Purpose: Myopia has reached “epidemic” proportions, especially in several East Asian countries. Most myopia emerges during childhood, particularly during the school years. The aim of this study was to investigate myopia prevalence and compare risk factors of myopia among Hong Kong Chinese primary school children under 2 different educational systems.
Design: Cross-sectional study
Methods: Visual assessments were conducted in 1 government-funded primary school (n = 159) and 1 international school (n = 223) in Hong Kong in September and October 2018, respectively. Measurements were performed on children aged 8 to 10 years old. Noncycloplegic refraction and axial length were measured, respectively. A validated questionnaire focusing on demographic information, nonscreen time (eg, reading and writing on paper materials), screen time (ie, smartphones and tablets usage), time spent on outdoor activities, and other myopia risk factors was completed by parents of participants.
Results: The prevalence of myopia [37.5% vs 12.8%, P < 0.001; spherical equivalent refraction (SER) ≤ –1.00 diopter (D)] and refractive astigmatism [25.0% vs 7.2%, P < 0.001; cylinder (Cyl) ≥ 1.00 diopter cylinder (DC)] were significantly higher in the local school than in the international school. Students in the local school were slightly older than those attending the international school (9.17 ± 0.82 years vs 8.95 ± 0.85 years, P = 0.046), and there was no significant difference in gender distribution between the 2 schools (P = 0.51). There were significant differences in the demographic information including parental myopia (P < 0.001), family income (P < 0.001), and parents’ educational level (P < 0.001) between the 2 schools. Multiple regression analysis showed that parental myopia history and continuous near work was associated with myopia in the local school, while the father's educational level was related to myopia in the international school.
Conclusions: In this pilot study, despite the much higher prevalence of parental myopia and high myopia in the international school, the myopia prevalence among the students is lower in this school than in the local school, suggesting that environmental factors other than genetics might have a stronger protective effect in this school population.
Keywords: Astigmatism
School system
Publisher: Lippincott Williams & Wilkins
Journal: Asia-Pacific journal of ophthalmology 
ISSN: 2162-0989
DOI: 10.1097/APO.0000000000000486
Rights: Copyright © 2022 Asia-Pacific Academy of Ophthalmology.
This is an open access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBYNC-ND) (, where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.
The following publication Liang, Y., & Kee, C.-S. (2022). Risk Factors for Myopia in 2 Hong Kong School Systems: A Pilot Study. Asia-Pacific Journal of Ophthalmology, 11(1), 19-26 is available at
Appears in Collections:Journal/Magazine Article

Files in This Item:
File Description SizeFormat 
Risk_Factors_for_Myopia_in_2_Hong_Kong_School.5.pdf276.49 kBAdobe PDFView/Open
Open Access Information
Status open access
File Version Version of Record
View full-text via PolyU eLinks SFX Query
Show full item record

Page views

Citations as of May 15, 2022


Citations as of May 15, 2022


Citations as of May 12, 2022

Google ScholarTM



Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.