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PolyU researchers find astigmatism in children worsened amid pandemic class interruptions; DIMS Spectacle Lens proved effective in slowing myopia during lockdown

26 Jan 2022

Research & Innovation School of Optometry

Two PolyU research teams found that myopia progression in schoolchildren has accelerated and the share of those with astigmatism has increased almost by half. Prof. David Shum, Dean of Faculty of Health and Social Sciences (3rd from left) attended the press conference with the researchers: Dr Kee Chea-su, Associate Prof. and Acting Head of School of Optometry (1st from right); Associate Prof. Dr Henry Chan (2nd from left); Research Assistant Prof. Dr Rachel Chun (1st from left); Research Assistant Prof. Dr Jeffrey Leung (3rd from right); and Postdoctoral Fellow Dr Choi Kai-yip.

Dr Henry Chan, Associate Prof. of PolyU’s School of Optometry, said that the DIMS Spectacle Lens co-developed by PolyU and Hoya Vision proved effective in slowing myopia by half under the extreme circumstances of the pandemic.

Dr Jeffrey Leung, Research Assistant Prof., School of Optometry at PolyU, said the study has shown that the share of schoolchildren with astigmatism has increased significantly since the suspension of face-to-face classes.

The COVID-19 pandemic has led to the suspension of face-to-face classes for a considerable period of time over the past two years. During this period, two research teams from The Hong Kong Polytechnic University (PolyU) found that myopia progression in schoolchildren has accelerated and the share of students with astigmatism has increased almost by half.

The researchers advised parents and schoolchildren to protect their vision health during stay-at-home learning, and consider multi-pronged approaches to alleviate the adverse impact of the pandemic, like changing lifestyles or considering wearing suitable and more effective glasses.

It is estimated that over 80 per cent of global students experienced class suspension or online learning at the height of the pandemic lockdowns, according to UNESCO, and Hong Kong students were no exception. In addition, less outdoor activities could also result in schoolchildren spending more time on electronic gadgets.

In a pioneering study about how the pandemic may affect schoolchildren’s astigmatism, a PolyU School of Optometry research team compared both cross-sectional and longitudinal data and found there was a significant increase in astigmatism after face-to-face classes were suspended.

The team compared the vision screening results of students aged 8 to 10 years old in a local primary school in October 2018 (112 students) and June 2020 (173 students). The share of children with astigmatism in 2020 was 49.1 per cent, or nearly 1.5-fold higher than that of 33.9 per cent in 2018.

Among the 38 children who participated in both the 2018 and 2020 studies, the share of those with astigmatism doubled, from 34.2 per cent to 73.7 per cent. This contradicts previous studies from pre-pandemic Hong Kong, Taiwan and the United States which show that astigmatism normally drops during childhood.

Dr Jeffrey LEUNG, Research Assistant Professor of the School of Optometry at PolyU, said, “Our survey also found that during the suspension of face-to-face classes, schoolchildren spent on average 30 to 60 minutes longer a day on digital screens like smartphones and tablets in their leisure time. Previous studies showed that the reading environment can indirectly or directly lead to astigmatism. Prolonged reading or usage of these electronic gadgets could worsen astigmatism.”

Meanwhile, another PolyU team released their first longitudinal study on how a PolyU innovated special lens for myopia control fares in the extreme circumstance of the novel coronavirus pandemic.

Under normal circumstances, the Defocus Incorporated Multiple Segments (DIMS) Spectacle Lens, co-developed by PolyU and Hoya Vision, can slow down myopia progression by 60 per cent. Researchers found that even with more rapid myopia progression during the pandemic lockdown measures, the DIMS lens was associated with a 46 per cent lower degree of myopia progression in comparison with conventional single vision lens (SVL). Furthermore, in the student group that spent more time in lockdown, the advantage of the DIMS lens was more prominent and slowed down myopia progression by 52 per cent.

The research team analysed 171 Hong Kong schoolchildren aged 7 to 13 in 2019 and during school suspensions in 2020. Among them, 115 students were beneficiaries of the “PolyU-HKIF Children Eye Care Programme”, and were provided with the DIMS Spectacle Lens during the research period. The other 56 schoolchildren in the control group wore SVL.

Dr Henry CHAN, Associate Professor of PolyU’s School of Optometry, said, “Our findings showed that schoolchildren who were more affected by school suspensions experienced an average increase of 35 degrees of myopia in the DIMS group, and 73 degrees in the SVL control group. The changes in teaching and learning under the pandemic have led to an increase in the time spent on electronic devices and near-vision work activities for children while less time was spent outdoors, which in turn aggravated the risk of myopia progression. The research findings provide reference data for frontline eye care practitioners to provide appropriate myopia management solutions to affected students.”

Dr KEE Chea-su, Associate Professor and Acting Head of PolyU’s School of Optometry, said, “Our two studies show that the pandemic poses an adverse impact on myopia and astigmatism among schoolchildren. Parents and children themselves are advised to take multi-pronged measures to protect their vision health, including maintaining correct reading postures and sufficient light, increasing the time for outdoor activities, and reducing the time spent on near-vision work activities. Parents are encouraged to take their children to receive eye exams to identify eye problems at an early stage. They should consult professional optometrists for getting suitable and effective glasses if needed.”

The two PolyU research studies were published in the international academic journals Clinical and Experimental Optometry and JAMA Network Open in mid-January 2022.



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Miss Annie Wong

Manager, Communications and Public Affairs

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Senior Manager, Communications and Public Affairs

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