Abstract
Myopia, the most common refractive error, is the most common cause of avoidable visual impairment among children and has reached epidemic proportions among children and young adults in urban areas of East and Southeast Asia that contain populations of Chinese ancestry. Moreover, vision health is an important theme of the health-promoting school program issued by the Ministry of Education in Taiwan. The aim of this study is to assess the impact of pre- and post-intervention proposed by the health-promoting school (HPS) model. The objectives are to understand whether the HPS model influenced the vision screening results and the attitude, knowledge level, and vision care behavior of the students involved. A prospective cohort study design was used to evaluate a vision health program. Four elementary schools, local education authorities, and one university in northern Taiwan established a coalition partnership to design a six-month program to combat myopia among students. The target population was 6668 school children from local elementary schools. For the purpose of this study, the outcome of visual acuity testing (in logMAR) was analyzed with a sampling of 373 school children (aged 11–12 years old) who were chosen from high prevalence of poor vision classes. After the HPS program, the attitudes, behaviors, and knowledge levels of the school children regarding vision health were significantly improved. The pre-intervention mean logMAR of all participating students (N = 373) was –.10, which increased to –.19 after the intervention. Analysis using the Wilcoxon signed-rank test showed that the logMAR value was significantly improved after the intervention (t = 2.13, p < 0.05). Our findings highlight the relevance and effectiveness of the coalition’s efforts, which reinforces the usefulness of co-operatively implementing the HPS program.
Introduction
The World Health Organization (WHO) has estimated that 12.8 million children aged 5–15 years old worldwide are visually impaired due to uncorrected refractive errors (REs) (1). Myopia, the most common refractive error, is the greatest cause of avoidable visual impairment among children and has reached epidemic proportions among children and young adults in urban areas of East and Southeast Asia with populations of Chinese ancestry, including China (2,3), Hong Kong (4), Singapore (5–7), and Taiwan (8–10). Myopia is most likely to develop among primary school students, presenting typically between 8 and 12 years of age (10,11). Children between the ages of 10 and 11 who have myopia generally show higher myopia progression rates (2). Longitudinal studies have shown that with no intervention, the incidences of refractive error among school children increased with age at a rate of 10% per annum (12).
School myopia is multifactorial, and its prevalence may fluctuate according to various environmental factors such as dim reading illumination (13) and individual behavior such as decreased time spent outdoors (14) and increased time spent on near work (15). Approximately 80% of school-age myopia is avoidable, resulting from conditions that could have been either prevented or controlled if knowledge and comprehensive intervention had been applied in a timely manner to reduce the vital risk factors of myopia among school children (16).
The WHO stated that ‘An effective school health program can be one of the most cost effective investments a nation can make to simultaneously improve education and health’ (17). The goal of WHO’s global School Health Initiative was to promote school health programs to prevent important health risks among youth and to engage the education sector in efforts to change the educational, social, economic and political conditions that affect risk (18,19). The Health Promoting Schools (HPS) model has become a major theme in health and educational strategies, providing a widely accepted framework for school-based activities to promote health (18,20). The HPS is whole-school approach and the HPS for many health issues can be effective such as in healthy eating, healthy weight, and sex education (21–23). In 2008, the Ministry of Education of Taiwan announced that all primary and middle schools were required to implement the HPS program to improve students’ health (24).
The Ministry of Education in Taiwan proposed a series of vision health policies or programs and encouraged school members, including teachers and nurses, to establish a coalition partnership with community members to reduce the threats of developing myopia at school-going age. Knowledge, attitude, and behavior of students have been essential components in evaluating school health programs (25). For considerations of program effectiveness and efficacy, a practical and beneficial method for evaluating the visual health of children is a crucial issue in school programs. The American Academy of Ophthalmology (26) and previous studies (27–29) recommend visual acuity (VA) testing as the standard of care for screening children three years of age or older and can provide results that are sensitive and specific enough for detecting myopia. Indeed, the Ministry of Education in Taiwan (30) indicates that measurement of visual acuity is a most sensitive test of the integrity of the visual system and fulfills all standard criteria of a good screening test: (1) there is minimal cost or risk to the patient; (2) measurement can be performed quickly and easily; (3) there is a high prevalence of detectable abnormalities; and (4) abnormalities are most often amenable to treatment.
Previous studies of myopia or refractive errors are based mostly on the medical perspective, focusing mainly on changing trends in prevalence (31,32) and the effects of treatment-oriented strategies for the populations at risk of myopia such as atropine therapy (33) and single vision lenses (14). A limited study on vision health based on HPS programs was conducted. The aim of this study is to assess the impact of pre- and post-intervention proposed by the HPS model. The objectives are to understand whether the HPS model influenced the vision screening results and the attitude, knowledge level, and vision care behavior of the students involved.
Methods
Project structure
A prospective cohort study design was used to evaluate a vision health program. Vision health is an important theme of the HPS program issued by the Ministry of Education Taiwan (30). The vision health program was reinforced through the HPS program by the fact that the local school authorities pressured the principals of schools that had an abnormally high rate of VA to develop a school profile in 2010.
Participants
Five schools were assigned by the education bureau of local counties and one school dropped out of the program due to inconvenience in conducting the interventions. During the program, 6668 students in four elementary schools were exposed. We consider that the large survey numbers in this study may be a burden for school teachers. Thus, only specific classes were chosen based on higher prevalence of abnormal vision in grades 3–4 students (11–12 years old) from the four schools to analyze the program outcome. Using purposive sampling, a total of 15 classes and their mentors participated. Sample size was determined based on simple random sampling with an alpha level of 0.05, a sampling bias of 0.05, and a population size of 37,616, resulting in a minimum required sample size of 380 for this study. All participants were exposed in the HPS program and their visual acuity test was performed before the intervention. All participants were categorized under three groups including the abnormal VA group (VA < 0.5), high-risk group (VA 0.6–.8) and normal VA group (VA > 0.9). The participating teachers assisted by sending the VA questionnaire to students and observed students’ outdoor activities.
Procedures of vision health interventions through the HPS model
This program adopted the whole-school approach of health-promoting schools by St Leger and Young (34) and the framework as follows:
Curriculum, teaching, and learning
First, teachers who were interested in the HPS program were asked to design vision health projects that could be structurally embedded into their curriculums, rather than being disjointed and sporadic. The core themes included outdoor activities for 120 minutes every day, the practice of taking 10-minute breaks after every 30-minute period of near work using the eyes, and a limited two hours of using computer-like devices were integrated into every curriculum as much as possible.
School organization, ethos, and environment
To disseminate news and information on HPS to students, parents, teachers and local community members, section chiefs of health in each school created wallboards and school bulletins. Students were encouraged to go out of the classroom during class breaks, managers in each selected school made traditional toys and game equipment like whipping tops, jump ropes, and outdoor shooting machines available on campus. Students were rewarded for their healthy behavior. School dietitians designed healthy school lunches containing nutritious ingredients and provided Chinese herb tea that promoted vision health.
Partnerships and services
This program featured a collaborative partnership between schools, local education authorities, and university support networks. The participating schools set up a special HPS committee and assigned one principal as the leader of the committee. Team members including experts from neighboring universities, school health center leaders, school nurses, and teachers met regularly to discuss the HPS interventions, share their experiences and monitor the achievements of each strategy.
Measures
Visual acuity testing
The Snellen E chart visual acuity test (five optotypes per line; testing distance: 6 m; Taiwan Instrument Co., Taipei, Taiwan) was performed as previously described. LogMAR was derived from the Logarithm of the Minimum Angle of Resolution and used to represent an individual’s visual acuity (28). The letter size of each line in the Snellen chart was designated as the logarithm to the base 10 of decimal visual acuity, so the 6/6 (or 20/20) line is LogMAR 0.00 and the 6/60 (20/200) line is LogMAR 1.0 (35).
Visual acuity assessments were performed monocularly (right eye, RE) with the subject’s habitual refractive correction, if any. The whole procedure was conducted under a standard protocol by the school nurses in the selected schools. The visual acuity of all participants was assessed before the intervention and participants were categorized under three groups including the abnormal VA group (VA < 0.5), high-risk group (VA 0.6–.8) and normal VA group (VA > 0.9).
Knowledge, attitude, and behavior of vision health against myopia
The vision care knowledge, attitude, and behavior scale used in this study was adapted from the Taiwan Ministry of Education Department’s ‘school children vision care 5-year plan’, related literatures, and vision care life skills provided by the Taiwan Ophthalmology Blindness Prevention Education Research Medical Association (25). The scale was validated by the team from Taiwan’s Health Promoting School, with an acceptable reliability (Cronbach α > 0.07, KR-20 > 0.90) as well as the expert’s validity (36). The scale consisted of 27 items, which included the following:
Vision Health Knowledge (Section 1, Items 1–9): Items from this section were gathered by asking participants to tick the correct answers regarding vision health. Correct responses were given a score of ‘1’. Incorrect or blank responses were given a score of ‘0’.
Vision Care Attitude (Section 2, Items 10–16): Attitudes of children toward vision care were gathered by asking participants to circle ‘agree’ or ‘disagree’ for each numbered option. A response of ‘1’ indicated agree and a response of ‘0’ indicated disagree.
Vision Health and Vision Care Behavior (Section 3, Items 17–27): The behaviors regarding vision health and vision care that children identify were gathered by asking participants to circle responses ranging from ‘completely fail to perform’ (1 point) to ‘performed daily’ (5 points) for each numbered option.
Data analysis
The Statistical Package for the Social Sciences 17.0 software (SPSS Inc, Chicago, IL) was used to perform the calculations. Since the data were normally distributed, the scores for knowledge, attitudes, and behaviors related to vision health before and after the intervention were tested using the Student’s Paired-Samples t Test. The values of LogMAR were naturally interval data while not normally distributed, so the difference in LogMAR between pre- and post-intervention was compared using the Wilcoxon signed-rank test. A p value below 0.05 was considered statistically significant.
Ethical considerations
The Ethical Review Committee of Chang Gung Hospital (Linkou, Taiwan) approved this study. All children and their parents/guardians, and school teachers were given an invitation letter and were fully informed of the purpose, methodology, and significance of the study. Written consent forms from children, children’s parents/guardians and school teachers were obtained. Researchers visited all participating classes in person and explained all the processes and procedures of the study. It was difficult to visit all parents/guardians. In the consent form, we provided all contact information including phone number (24 hours), email, and mailing address for parents/guardians; if they had any questions, they could contact us at any time. Alternately, they could also contact the participating teachers who were our team members. They were informed that they could withdraw at any stage without adverse personal consequences.
Results
Outcomes for knowledge, attitude, and behavior regarding vision health
During the period from November 2010 to April 2011, we collected questionnaires from 390 children, a total of 373 grade 3 and 4 students participated in this study, of whom 49.6% were girls and 50.4% were boys. The knowledge scores increased from 7.99 to 8.55 (t = 6.96, p < 0.001), attitude scores increased from 6.16 to 6.51 (t = 3.25, p < 0.01), and behavior scores increased from 37.22 to 39.32 (t = 3.89, p < 0.001) after intervention (Table 1).
Comparison of mean scores of knowledge, attitudes, and behaviors for vision health between pre- and post-intervention (N = 373).
p < 0.05; ** p < 0.01; *** p < 0.001.
Specifically, scores for five items of knowledge regarding vision health increased significantly after intervention, including early symptoms of vision impairment (t = 3.11, p < 0.05), time spent on near work (t = 6.07, p < 0.001), reading illumination (t = 2.08, p < 0.05), nutritional intake for vision health (t = 2.57, p < 0.05), and outdoor activities (t = 2.16, p < 0.05). Attitudes toward wearing spectacles (t = 2.64, p < 0.05) and access to optometrists for prescription glasses (t = 3.18, p < 0.05) also presented significantly positive changes after intervention. The frequency of the five preventive behaviors over the last seven days include the cumulative time spent on watching TV and using the computer (t = 3.24, p < 0.01), correct reading posture (t = 1.98, p < 0.05), nutritional intake for vision health (t = 2.30, p < 0.05), exercises for ocular relaxation (t = 2.74, p < 0.05), and outdoor activities (t = 3.12, p < 0.05) increased after the six-month intervention.
Changes of visual acuity testing between pre- and post-intervention
The pre-intervention mean logMAR of all participating students (n = 373) was −0.10, which increased to −0.19 post-intervention. The result showed that the logMAR value was improved significantly after the intervention (z = 2.13, p < 0.05). The percentage of students with a VA below 0.8 decreased by 1.3% after the intervention (n = 217, 58.1% vs. n = 212, 56.8%).
According to the referral criteria issued by the Ministry of Education Taiwan (25), students were categorized under three groups (abnormal VA group, high-risk group, and normal VA group) for subsequent analyses. Table 2 explains the shift in the three groups. The proportion of the abnormal VA group increased by 3.5% after the HPS program (n = 113, 30.3% vs. n = 126, 33.8%), the proportion of the high-risk group decreased by 4.8% (n = 104, 27.9% vs. n = 86, 23.1%), and the proportion of the normal VA group increased by 1.4% (n =156, 41.8% vs. n = 161, 43.2%). Based on these changes in the proportions, a higher proportion of the high-risk group shifted to the normal VA group than to the abnormal VA group (n = 29, 7.8% vs. n = 21, 5.6%) after the HPS program. Among students with normal VA prior to the intervention, 6.7% (n = 25) shifted to the high-risk group and 0.8% (n = 3) to the abnormal VA group after the HPS program.
Change in groups of visual acuity testing after intervention (N = 373).
The logMAR value for each participating student was calculated to examine the vision outcomes of the HPS program. Decreases in the logMAR value after the intervention were classified as an improvement, increases in the logMAR value were classified as deterioration, and unchanged logMAR values were classified as no change. Table 3 shows the percentage of improvement in the visual acuity test in each group pre- and post-intervention. Of the students who had refractive errors, 37.2% (n = 42) of them showed maintained vision after the intervention, 34.5% (n = 39) improved their vision, and 28.3% (n = 32) showed a deteriorated VA. For the high-risk group, 39.4% (n = 41) showed a deteriorated VA, 34.6% (n = 36) showed improved VA, and 26.0% (n = 27) maintained their vision. Among the students with normal vision, 28.4% (n = 44) demonstrated VA improvement after the intervention, 49.7% (n = 77) maintained their VA, and 21.9% (n = 34) experienced VA deterioration. The results indicated that the HPS program was an effective strategy to delay vision deterioration.
Change of visual acuity testing after vision health intervention (N = 373).
Additional summary of comments from participating teachers
Since the participation of the three schools is the result of pressure put on school principals by the local school authorities to take part in the program, team members and teachers in the assigned schools initially expressed some reluctance to assist in conducting the program. Some changes were indicated by participating teachers, after having co-operated with the committee in the coalition partnership. Particularly, all the teachers regarded the school as a place where life skills involving health must be taught through active engagement in HPS intervention with students simultaneously. To achieve the goal of core activities of the HPS program for students, participating teachers actively searched for vision health-related information to design curriculums and materials. Moreover, they reminded parents to monitor their children’s eye use behaviors during vacations. Finally, the feedback from teachers showed that most of the teachers were happy to accept responsibility for student education in performing healthy behaviors. Positive changes in motivation, perception and responsibility of teachers were evident after their participation in the HPS program.
Discussion
The findings of this study indicate that vision health initiatives through HPS programs can improve or maintain vision deterioration in school-age children with the change in visual acuity. We compared our results with the annual increase in the prevalence of abnormal VA in the national report and with long-term observational studies, which provide a comparable standard to highlight the importance of this study. Findings from previous studies show that when no intervention is provided for vision impairment in school children, abnormal refractive issues worsen with age (2,28). Taiwanese census data indicate that vision impairment increases at a rate of 7% per school year. This study selected school children from a county in northern Taiwan as a sample, and the ratio of participating students with VA less than 0.8 decreased by 1.3% after the intervention. This finding indicates that the HPS intervention influenced the abnormal refractive progression. It may also reveal that a benefit of the intervention in this study is that it could delay vision deterioration.
In fact, vision impairment is irreversible. Previous studies have shown that abnormal ocular refraction is irreversible after a diagnosis of myopia (37). We found that the rate of students in the high-risk group, had their vision restored sufficiently, were reclassified into the normal VA group. Individual assessments of school children in this study also showed that their VA either remained the same or showed delayed deterioration of vision. This finding further validates the study by Xiang et al. (2), which found that eyes with normal vision or myopia undergo increased refraction relatively slowly, whereas eyes that are just beginning to develop myopia undergo increased refraction relatively quickly.
There is a lack of research on school-based visual impaired intervention programs and previous studies are based on medical perspectives which are unable to provide references of myopia case management for schools (7,38,39). The HPS is effective to prevent myopia because lifestyle and risk behaviors related to myopia are learned early at school age. The HPS takes a whole-school approach to health in which a broad health education curriculum and activities are supported by the environment and ethos of the school (21,22).
This study recommends local governments to adopt our HPS process and modify it according to local school health policies so that it can be implemented in those schools that have a high prevalence of REs and by forming committees to establish coalition partnerships with community resources. Moreover, for effective vision care programs, it is important to classify VA results to determine the extent of vision impairment, and different interventions should be provided for specific groups. Schools can collaborate with ophthalmologists to provide integrated vision care for students in the high-risk groups to prevent vision problems early on. Because the high-risk groups for myopia can only be approached and identified through regular school vision screening, preventing vision deterioration in school children requires the incorporation of efforts by both the educational and healthcare sectors to manage cases using referred standards and criteria for risk groups. The results emphasize school prevention and health promotion in visual health: provide school teachers with greater understanding of the effectiveness of HPS programs; allow them to deliver high-quality visual health activities; and apply a comprehensive and multifaceted approach to promoting healthy behaviors.
Despite its contributions, this study has several limitations. Purposive sampling was used and thus may not necessarily represent average school children. This HPS program incorporates only a one-group pre-test–post-test design so its ability to establish a real, causal relationship between the effect of HPS and vision health outcomes may be limited. We suggest that future studies incorporate the participation of ophthalmologists to design effective tools for preventing and controlling the progression of myopia in children. Future studies can include control samples and extended intervention durations, and validated checklists to record behavioral changes so as to precisely demonstrate the effectiveness of vision health promotion through the HPS program.
Conclusions
Myopia is a significant, prevalent disease in children. Our findings highlight the relevance and effectiveness of the coalition’s actions, reinforcing for schools the utility of joining and conducting HPS programs co-operatively. The lessons drawn from the evaluation of the coalition partnership for vision health could serve as a guide for implementing practical HPS strategies to prevent myopia among students.
Footnotes
Funding
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
