Effect of School-Based Family Health Education via Social Media on Children’s Myopia and Parents’ Awareness: A Randomized Clinical Trial

Key Points

Question  Can school-based family health education via social media control the development of myopia in children?

Findings  In this cluster randomized clinical trial of 1440 children, the 2-year cumulative incidence rate of myopia in the intervention group (106 of 544 [19.5%]) was lower than that of the control group (171 of 700 [24.4%]), but the mean myopic shift difference was less than 0.25 diopters and was not accompanied by any axial length differences.

Meaning  The findings of this study suggest that school-based, weekly family health education via a social media platform could prevent and control myopia in children; however, whether these findings extrapolate elsewhere in the world or are clinically relevant in controlling myopia in the long term is undetermined.

Importance  Myopia is a common cause of vision loss, and its prevalence is increasing globally.

Objective  To evaluate the effects of school-based family health education via WeChat in raising parents’ awareness of myopia prevention and behavior and in controlling the development of myopia in children.

Design, Setting, and Participants  A single-masked cluster randomized clinical trial of children was conducted from October 1, 2018, to December 31, 2020, among grade 1 students from 12 primary schools in Guangzhou, China. The 12 primary schools were randomly selected in 2 districts and randomized to the intervention and control groups. All grade 1 students were invited to participate, and 688 students were included in the intervention group and 752 in the control group.

Interventions  Weekly health education via the social media platform WeChat was provided to the parents in the intervention group.

Main Outcomes and Measures  Data include results of eye examinations of children and questionnaires completed by parents. The primary outcome was the 2-year cumulative incidence rate of myopia. Myopia was defined as a spherical equivalent (SE) refractive error (sphere of +0.5 cylinder) of at least −0.50 diopters (D). The secondary outcomes were the 2-year changes in the axis length and SE refraction, parental awareness, children’s screen time, outdoor activities, and learning tools during COVID-19.

Results  Among the 1525 children included at baseline (835 boys [54.8%]; mean [SD] age, 6.3 [0.5] years), 1244 competed the final assessment; the 2-year cumulative incidence rate of myopia was 106 of 544 (19.5%) in the intervention group and 171 of 700 (24.4%) in the control group (difference, 4.9% [95% CI, 0.3%-9.5%]; P = .04). The mean myopic shift in SE refraction in the intervention group (−0.82 D) was lower than that in the control group (−0.96 D; difference, −0.14 [95% CI, −0.22 to −0.06] D; P < .001). No difference in change in axial length was detected (difference, 0.02 [95% CI, −0.06 to 0.09] mm; P = .70).

Conclusions and Relevance  School-based weekly family health education via WeChat resulted in a small decrease in the 2-year cumulative incidence rate of myopia with a difference in SE of less than 0.25 D not accompanied by any axial length differences. Whether these findings extrapolate elsewhere in the world or are clinically relevant in the short or long term remain to be determined.

Trial Registration  Chinese Clinical Trial Registry Identifier: ChiCTR1900022236

Myopia is a common cause of vision loss that has increased in prevalence globally and is projected to affect nearly 5 billion people by 2050.¹ In East Asia, the prevalence of myopia has been reported to be exceptionally high (73%) among school-aged children,² and China is no exception.³ The prevalence of myopia among Chinese children and adolescents has been reported to be 53.6%, with 36.0% of children with myopia being primary school students.⁴ Early-onset myopia (aged ≤7 years) increases the risk of developing high myopia.⁵ High myopia is associated with various specific complications, including cataracts, chorioretinal atrophy, macular holes, myopic foveoschisis, and optic nerve head changes, which may lead to irreversible retinal photoreceptor damage and even central visual loss, ultimately generating a heavy burden for individuals, families, and society.⁶

Although both genetic and environmental factors contribute to myopia, recent dramatic changes in the prevalence of myopia are thought to mainly reflect environmental influences.^7,8 Environmental factors mainly include vision-related health behaviors, such as outdoor activities, eye-using habits, electronic screen time, and sleep.² Controlling these factors can effectively prevent and control myopia in children.⁹ However, the success of any strategy that requires children’s behavioral modification or acceptance of new treatment regimens is likely to depend on parents’ awareness of the condition and their acceptance of the proposed interventions as a necessary treatment option.¹⁰ Many studies have demonstrated that directly targeted interventions with families are effective in helping children to decrease obesity by influencing parental attitudes and behaviors.^11,12 These factors appear to be equally important for future myopia management strategies. Thus, raising parental awareness of myopia prevention is essential for the control of early myopia in children.¹⁰ As proposed in the 2018 World Health Organization Regional Office for the Western Pacific, the International Agency for the Prevention of Blindness, and the Brien Holden Vision Institute Meeting on Myopia, one of the primary myopia control strategy recommendations is to increase public education and thereby raise parents’ awareness.¹³ Therefore, raising parents’ awareness of myopia prevention and control through family health education is an important way to cultivate vision-related health behaviors in children. Currently, the popularity of smartphones has encouraged their use in health management.¹⁴ Mobile platforms are easier to implement widely and are more cost-effective than traditional forms of health education.¹⁵ WeChat, one of the most popular social media platforms in China, has been used in randomized studies on various diseases for health education and management.^16-18 However, to our knowledge, there have been no reports of health education based on the WeChat platform for myopia control in children in China. This study aimed to evaluate the effects of school-based family health education via WeChat in raising parents’ myopia prevention awareness and behavior and in controlling the development of myopia in children.

This school-based, cluster randomized trial was conducted in Guangzhou, China. The study was approved by the institutional review board of Sun Yat-sen University, School of Public Health, and all parents provided written informed consent for their children to participate. This study followed the Consolidated Standards of Reporting Trials (CONSORT) reporting guideline. A copy of the trial protocol is available in Supplement 1.

Two districts with similar socioeconomic levels were selected. All public primary schools in each district were numbered (36 schools in district 1; 38 schools in district 2), and 6 schools were randomly selected from each district. Among the schools selected in each district, 3 were assigned to the intervention group, and 3 were assigned to the control group. This process was performed by using SPSS, version 25.0 (IBM Corporation). Single blinding was used so that the ophthalmic examiners (F.Z. and Y.H.) were blinded to the group randomization. All grade 1 students (the age range can be very different between countries) from the selected schools were invited to participate in this study, with a response rate of 1525 of 1779 (85.7%). Students with serious systemic or ophthalmic diseases or who had undergone myopia-related surgery were excluded.

At baseline, information on the visual status of students and their parents’ awareness of myopia prevention was collected, and they were followed up for 2 years. Details of the study design are shown in the Figure.

Before the baseline investigation, all 12 participating schools held information seminars for the parents, with the primary aim of motivating and informing them of the possible discomfort after undergoing cycloplegic refraction. Next, parental consent forms for cycloplegic refraction and for the questionnaire were collected, and only students whose parents agreed to both were enrolled at baseline.

The intervention consisted of sending health education for parents by head teachers through WeChat, including increasing outdoor sun-exposed activities, correcting eye use behavior, and limiting electronic screen time. The intervention messages were sent every Monday from December 1, 2018, to December 28, 2020 (except for the month of the Chinese Lunar New Year, when parents and teachers were celebrating the holiday and cooperation would have been low). The intervention flowchart is shown in the eFigure in Supplement 2.

Eye examinations were performed in the schools by 5 optometrists and 4 ophthalmic physicians (including F.Z. and Y.H.) who were blinded to the group randomization. Axial length was measured by using a biometer (IOLMaster; Carl Zeiss Meditec). Cycloplegia was induced with 3 drops of cyclopentolate hydrochloride, 1%, administered at 0, 5, and 20 minutes to both eyes. Pupil dilation and pupil light reflex were checked after 15 minutes to determine whether full cycloplegia (pupil dilated ≥6 mm and pupil light reflex absent) was achieved. Autorefraction was measured using a commercially available device (KR-8800; Topcon). All measurements were performed 3 times in each eye, and the mean value was calculated for each eye. The students’ weight and height were also measured. The follow-up eye examinations were the same as those at baseline and were performed by the same ophthalmology team using the same equipment.

The electronic questionnaires were sent out within 1 week after a school completed eye examinations, and they were answered by parents (or guardians). The teachers reminded parents to complete the questionnaire. Then, in the first, second, and third weeks after the questionnaire was sent out, study staff checked and returned the list of parents who had not completed the questionnaire to the teachers, who urged these parents to complete the questionnaire.

In the second year of this study, the COVID-19 outbreak occurred in China, and the government adopted a policy of home confinement and online learning (lasting for 3 months in Guangzhou primary schools). We added questions about it to the follow-up questionnaire. The questionnaire was shown in the eMethods in Supplement 2. Eye examinations and questionnaires were administered from November 1 to December 31 at both baseline and follow-up.

The primary outcome was the 2-year cumulative incidence rate of myopia. Myopia was defined as a spherical equivalent (SE) refractive error (sphere of +0.5 cylinder) of at least −0.50 diopters (D).¹⁹ The secondary outcomes were the 2-year changes in the axis length and SE refraction. The development of myopia was defined as the progression of SE refraction with 0.50-D increments. Only students without myopia based on the baseline cycloplegic refraction data were selected for the final analysis after the 2-year follow-up. In addition, changes in parental awareness, children’s screen time, outdoor activities, learning tools, and indoor activities during the period of the outbreak of COVID-19 were used to evaluate the effects of the intervention.

The sample size was calculated according to a formula commonly used for counting material in experimental epidemiological study designs. The incidence of myopia in the control group was estimated to be 10% per year from grade 1 to grade 3²⁰; the expected reduction in the myopia incidence was set at 8% during the 2-year study. A 2-sided α of .05 and a power level of 95% were assumed. Further, the assumption of a 2-year loss to follow-up of less than 15% and a baseline participation rate of 90% led to a total sample size of 1420 students. Each public primary school in Guangzhou had a mean of 120 students in grade 1,²¹ meaning that at least 12 primary schools were needed.

Children’s cumulative incidence rate of myopia was compared between the intervention and control groups using a χ² test. Cumulative variances in SE and axial length were analyzed by the linear mixed model to correct for the random effects of cluster design and adjusted for age, sex, body mass index, and the number of parents with myopia. Distribution of parental awareness, children’s myopia development, learning tools, and indoor activities during home confinement were compared between the 2 groups using χ² tests.

Because the refraction and biometry of the right and left eyes were highly correlated, we used data from the right eye for analysis. If the data for the right eye were missing, the left eye data were used. If data were missing for both eyes, this participant was excluded from the analysis. No data were missing in the electronic questionnaire because it can be set to a mandatory mode.

All statistical analyses were performed using SPSS, version 25.0 (IBM Corporation). All P values were 2 tailed, and P ≤ .05 indicated statistical significance for the primary outcome but not for other P values, because there were no adjustments to P values for multiple analyses.

A total of 1525 students were included at baseline (724 in the intervention group vs 801 in the control group). The mean (SD) age of all students was 6.3 (0.5) years, ranging from 6 to 7 years; 835 students (54.8%) were boys and 690 (45.2%) were girls. At baseline, 85 students (5.6%) had myopia and were excluded from further analysis (Table 1). A total of 1440 students (688 in the intervention group and 752 in the control group) continued to participate in this study, and 1244 (86.4%) completed the final assessment after the 2-year follow-up (544 [79.1%] in the intervention group and 700 [93.1%] in the control group). Data from a total of 1231 participants involved the right eye (both eyes available, 1224; only the right eye available, 7), and data from 13 participants involved the left eye owing to missing right eye data.

The 2-year cumulative incidence rate of myopia in the intervention group (106 of 544 [19.5%]) was significantly lower than that in the control group (171 of 700 [24.4%]; difference, 4.9% [95% CI, 0.3%-9.5%]; P = .04). The mean myopic shift in SE refraction was less for the intervention group (−0.82 D) than for the control group (−0.96 D; difference, −0.14 [95% CI, −0.22 to −0.06] D; P < .001). No difference in change in axial length was detected (0.47 vs 0.49 mm; difference, 0.02 [95% CI, −0.06 to 0.09] mm; P = .70). The proportion of myopic progression of more than 2.00 D was lower in the intervention group (31 of 544 [5.7%]) than in the control group (67 of 700 [9.6%]; difference, 3.9% [95% CI, 0.8%-6.8%]) (Table 2).

After the 2-year intervention, a higher proportion of parents in the intervention group compared with the control group made rules for their children to watch television (460 of 544 [84.6%] vs 558 of 700 [79.7%]; difference, 4.9% [95% CI, 0.5%-9.1%]; P = .03) and play video games (474 of 544 [87.1%] vs 564 of 700 [80.6%]; difference, 6.5% [95% CI, 2.4%-10.6%]; P = .002) and engaged in outdoor activities more than 2 times per week (262 of 544 [48.2%] vs 292 of 700 [41.7%]; difference, 6.5% [95% CI, 0.9%-12.0%]; P = .04) (Table 3). Regarding learning tools during home study, the intervention group had higher use of televisions (169 of 544 [31.1%] vs 162 of 700 [23.1%]; difference, 8.0% [95% CI, 3.0%-12.9%]; P = .01) and lower use of mobile phones and tablets (273 of 544 [50.2%] vs 414 of 700 [59.1%]; difference, −8.9% [95% CI, −14.7% to −3.4%]; P = .01). Also, the intervention group had a lower rate of watching television (115 of 544 [21.1%] vs 205 of 700 [29.3%]; difference, −8.2% [95% CI, −12.9% to −3.3%]; P = .01) (Table 4).

eTable 1 in Supplement 2 shows parental participation in and satisfaction with the WeChat education in the intervention group. The overall proportion of parents who were satisfied with the WeChat education was 500 of 544 (91.9% [95% CI, 89.3%-93.9%]).

The impact of information contamination in this study was low, with a total of 90.1% of the parents (490 of 544) reporting that they had never retweeted the intervention messages or had retweeted them only once or twice during the entire study period (eTable 2 in Supplement 2). The characteristics were similar between the participants who received follow-up and those who did not (eTable 3 in Supplement 2). The intervention group and the control group received myopia prevention tips outside of the study at a similar frequency (eTable 2 in Supplement 2).

School-based weekly family health education via WeChat resulted in a small decrease in the 2-year cumulative incidence rate of myopia, with a difference in SE of less than 0.25 D not accompanied by any axial length differences. Whether these findings extrapolate elsewhere in the world or are clinically relevant regarding the long-term effect on controlling myopia remains to be determined. Enhancing public education and raising awareness of parents are key strategies for children’s myopia prevention.¹³ Zhou et al²² reported that parents’ attitudes toward their children’s visual health were strongly associated with myopia risk in school-age children. Xu et al²³ educated parents of grade 3 students about myopia prevention through parent-teacher conferences and one-on-one follow-up with key participants. After 2 years, the parents’ knowledge of myopia prevention increased significantly, but the incidence of children’s myopia between the 2 groups did not show a significant reduction.²³ This result can be explained by the peak age of myopia onset in children, which ranges from 8 to 10 years^24,25 (usually in grades 3-5 of primary school in China). Many children already had myopia and developed stubborn eye use behaviors that are difficult to correct through family health education at this age. The intervention was implemented so late that it could not result in a significantly lower incidence rate of myopia in the intervention group compared with the control group.

We did not find a difference in the cumulative change in axial length. Similarly, He et al²¹ effectively reduced the incidence rate of myopia but not axial length in children by increasing outdoor activity. One possibility for this apparent discrepancy is that the differences in these studies for SE are owing to chance or confounding factors. Another possible explanation is that the change in the axial length and SE refraction are not synchronized before and after myopia onset in children. Children who develop myopia have had longer axial length 3 years before the onset. Refractive changes in SE occurred 1 year later than changes in axial length.²⁶ Second, after myopia onset, axial length continued to progress at a slower rate than the year before onset. The control group had a higher proportion of children with myopia, so the growth rate of axial length might be lower than that in the intervention group. Consequently, the gap of changes for axial length between the 2 groups was narrowed.²⁶

The findings in this study also suggest that parents in the intervention group, on average, may have made positive improvements in their children’s electronic screen use and the frequency of outdoor activities compared with the control group. Both electronic screen use^27,28 and outdoor activity^21,29,30 have recently been reported as key factors influencing the onset and progression of myopia in school-age children. According to the information-motivation-behavior theory,³¹ information changes people’s attitudes, contributes to behavioral motivation, and ultimately contributes to relevant behaviors. Thus, accessible and stable attitudes persistently affect future behaviors.³¹ As such, positive parental attitudes can lead to effective healthy behaviors regarding children’s vision,^32,33 further reducing their incidence of myopia.

During the COVID-19 outbreak, people were prevented from going outdoors to protect them from the virus and to better intercept the spread of the virus. Both groups spent more time watching television, but viewing time was reduced in the intervention group compared with the control group. In addition, the children in the intervention group had a higher rate of using television and a lower rate of using mobile phones or tablets for home learning than those in the control group. Previous studies have shown that watching television involves a greater distance between the eyes and a screen and is thus less harmful to the eyes than smartphones or tablets.³⁴ Although home confinement during the COVID-19 pandemic increased the risk of myopia for children aged 6 to 8 years,³⁵ this study found that the intervention group chose learning tools that were relatively more friendly to the eyes and maintained healthier eye use behaviors. This is because parents with a stronger awareness of myopia prevention play a positive role in controlling myopia in children.

WeChat has been shown to be effective in improving the mental health of patients with HIV³⁶ as well as helping people to lose weight.³⁷ We applied WeChat to myopia prevention and control in children and achieved high satisfaction; however, the participants were not masked, and there was no comparison group, so it was difficult to determine the relevance of this finding with certainty. A few parents were dissatisfied, mostly because some intervention messages were too long to read, suggesting that short and clear intervention messages are more conducive to intervention.

High parental involvement may depend on the fact that the publisher of the intervention messages was the head teacher. It may be common in China for parents to give more attention to advice from schoolteachers than from other social institutions. Traditionally, early school–aged children are inclined to follow their parents’ instructions in China. However, this intervention may not be applicable to other countries in the world owing to cultural differences.

The limitations of this study should be noted. First, the intervention messages were sent through the social media platform WeChat, which could be retweeted or shared with others. Therefore, we investigated retweeting among the parents of the intervention group. A total of 490 of 544 parents (90.1%) reported that they had never retweeted the intervention messages or had retweeted them only once or twice during the entire study period. Therefore, the impact of information contamination in this study was low (eTable 2 in Supplement 2). Second, withdrawal owing to refusal to complete the questionnaire or refractive examination was more frequent in the intervention group, which may have biased the results. However, eTable 3 in the Supplement 2 indicates that the characteristics were similar between the participants who received follow-up and those who did not. Third, the parents also received information about myopia prevention in their daily lives outside of this study, and the 2 groups may have differed in terms of the frequency with which they received such information, biasing the results. However, eTable 2 in the Supplement 2 shows that the 2 groups received myopia prevention tips outside the study at a similar frequency. Fourth, the intervention messages were sent to the parents by teachers, which may potentially have educated both the teachers and parents. Because the teachers’ attitudes and behaviors were not assessed, we could not determine whether the teachers played an active role in controlling myopia in this study.

In this cluster randomized clinical trial, school-based weekly family health education via WeChat resulted in a small decrease in the 2-year cumulative incidence rate of myopia, with a difference in SE of less than 0.25 D not accompanied by any differences in axial length. Whether these findings extrapolate elsewhere in the world or are clinically relevant in the short or long term remains to be determined.

Accepted for Publication: July 29, 2021.

Published Online: September 16, 2021. doi:10.1001/jamaophthalmol.2021.3695

Corresponding Author: Ciyong Lu, PhD, Department of Medical Statistics and Epidemiology, Sun Yat-Sen University School of Public Health, 74 Zhongshan Rd 2, Guangzhou 510080, China (luciyong@mail.sysu.edu.cn); Xiao Yang, PhD, Department of Refractive and Low Vision, Zhongshan Ophthalmic Center, Sun Yat-Sen University, 54 Xianlie South Rd, Guangzhou 510060, China (yangx_zoc@163.com).

Author Contributions: Dr Lu had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: J. Zhang, Y. Guo, Yang, Lu.

Acquisition, analysis, or interpretation of data: Li, L. Guo, Zhao, Hu, Du, S. Zhang.

Drafting of the manuscript: Li, J. Zhang, Zhao, Du.

Critical revision of the manuscript for important intellectual content: Li, L. Guo, Hu, Y. Guo, S. Zhang, Yang, Lu.

Statistical analysis: Li.

Obtained funding: Li, Lu.

Administrative, technical, or material support: Li, Zhao, Y. Guo, S. Zhang.

Supervision: Y. Guo, Yang, Lu.

Other (conducted the search and wrote the report): J. Zhang.

Conflict of Interest Disclosures: None reported.

Funding/Support: This study was supported by grant 2017A030313465 from the Natural Science Foundation of Guangdong Province and grant 201803010062 from the Guangzhou Municipal Science and Technology Project.

Role of the Funder/Sponsor: The sponsors had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Data Sharing Statement: See Supplement 3.