MINISTRY OF EDUCATION AND TRAINING THAI NGUYEN UNIVERSITY ------ VU QUANG DUNG STUDYING THE SCHOOL MYOPIA STATUS AND PREVENTIVE INTERVENTIONS FOR SECONDARY STUDENTS IN MIDLAND REGI
Trang 1MINISTRY OF EDUCATION AND TRAINING
THAI NGUYEN UNIVERSITY - -
VU QUANG DUNG
STUDYING THE SCHOOL MYOPIA STATUS AND PREVENTIVE INTERVENTIONS FOR SECONDARY
STUDENTS IN MIDLAND REGIONS
OF THAI NGUYEN PROVINCE
Speciality: Sociological Hygiene and Health Organization
Code number: 62.72.01.64
PHD THESIS SUMMARY
Trang 2The work was completed in College of Medicine and Pharmacy - ThaiNguyen University
Scientific supervisor:
1 Assoc Prof Dr Hoang Thi Phuc
2 Prof Dr Do Van Ham
Defender 1:
Defender 2:
Defender 3:
The thesis will be defended at the National level by the Board of
examiners in College of Medicine and Pharmacy - Thainguyen University in
September 2013
Thesis can be found at:
National Library
Resource Center ThaiNguyen University
Library of ThaiNguyen College of Medicine and Pharmacy
Trang 3LIST OF PUBLISHED PAPERS RELATED TO THESIS
1 Vu Quang Dung, Do Van Ham, Mai Quoc Tung, Vu Thi Kim Lien, Do Thi
Yen, Nguyen Manh Hung (2008), "Studying the status of school
sanitation in two junior schools in Thai Nguyen", the third International
Scientific Conference of Occupational Health and Sanitation, Hanoi, pp 279-286
2 Vu Quang Dung, Do Van Ham, Mai Quoc Tung, Vu Thi Kim Lien, Dang
Thi Tam, Nguyen Manh Hung (2008), "Initial studying on myopia in
junior students in Thai Nguyen", the third International Scientific
Conference of Occupational Health and Sanitation, Hanoi, pp 287-296
3 Vu Quang Dung, Do Van Ham, Mai Quoc Tung, Vu Thi Kim Lien, Do Thi
Yen, Nguyen Manh Hung (2008), "Studying the status of school
sanitation in two junior schools in Thai Nguyen", The seventh National
Occupational conferences, Medical Publishing, Hanoi, pp 70
4 Vu Quang Dung, Do Van Ham, Mai Quoc Tung, Vu Thi Kim Lien, Dang
Thi Tam, Nguyen Manh Hung (2008), "Initial studying on myopia in
junior students in Thai Nguyen", The report summarizes scientific,
scientific conferences nationwide Occupational Health Seventh, Medical Publishing, Hanoi, pp 71
5 Vu Quang Dung, Do Van Ham, Mai Quoc Tung, Vu Thi Kim Lien,
Nguyen Manh Hung, Do Thu Trang (2008), "The studying of refractive
errors in school students in Thai Nguyen province", in the National
Ophthalmology Conference, Ho Chi Minh City, pp 5
6 Vu Quang Dung (2008), "The studying on functional tests and the
Trang 4BACKGROUND
School myopia is increasing in many countries around the world as well as in Vietnam According to Kovin Naidoo (ICEE International Center for Eye Care Education), in 2020, the refraction and glasses account for 70% of the global population (5.3 billion people) In which myopia is 33% (3 billion people) Currently, Asia has the highest incidence of school myopia in the world In China (2006), there are more than 300 million people with myopia A study in India (2003) showed that 13% of blindness and 56% of people had visual impairment due
to myopia Thus, the program "Vision 2020" the World Health Organization ranked school myopia is one of the five causes of blindness in the prevention programs worldwide
According to the investigation of many researchers recently, myopia is increasing rapidly and it is the main cause of vision loss in Vietnam and other regional countries In Ho Chi Minh City (2006), published by Le Thi Thanh Xuyen showed the percentage of myopia students increased alarmingly The rate of myopia was 8.65% in 1994 up to 17.2% in 2002 and 38.88% in 2006 According to
a research by the Institute of Educational Sciences of Vietnam (2008), the prevalence of school myopia was high with an average of 26.14% of the total student’s population
There have been many studies on school myopia so far in both cities and rural areas in many provinces around the country However, there are no in-depth studies of school myopia in the Midland regions of the Northern Mountains Based
on the existent situation and concern for school myopia prevention, this study is undertaken with the aims:
1 To describe the situation and identify a number of risk factors for school myopia in secondary schools in midland regions of Thai Nguyen province in 2006
2 To assess the effectiveness of preventive interventions for school myopia for 2 years (2006-2008)
Trang 5CONTRIBUTIONS OF THE THESIS
1 Its is the opening study about myopia status and preventive measurements
in secondary school in Midlands of Thai Nguyen and the Northern Mountainous region
2 The study has built an intervention model: Combination of community and clinical interventions are effective, practical benefits and feasible It can be widely applied to midland and mountainous region
3 The study has identified a number of risk factors which associated with school myopia that other authors have not mentioned in Vietnam such as an association between myopia and light intensity in each location of the classroom; the relationship between myopia and suitable and unsuitable furniture size; relationship between myopia with outdoor playing time and myopia with family history
4 The study implemented solutions which combined health education and treatment intervention for preventing school myopia These interventions are feasible and are accepted by the community
THESIS STRUCTURE
The thesis contents 121 pages, including the following parts:
Introduction: 2 pages
Chapter 1 - Overview: 31 pages
Chapter 2 - Subjects and Methods: 18 pages
Chapter 3 - Research results: 39 pages
Chapter 4 - Discussions: 28 pages
Conclusions and Recommendations: 3 pages
The list of published articles: 1 page
And 148 references, including 66 Vietnamese and 82 English
The thesis has 41 tables and 5 charts and 4 diagrams
The appendix includes 9 appendixes in 37 pages
Trang 6Chapter 1 OVERVIEW 1.1 Status of school myopia recently
1.1.1 The concept
School myopia (nearsightedness) is acquired in school ages Degree of myopia ≤ - 6.00D Myopia is caused by the asymmetric axial length and the eye's optical power that makes light come in front of the retina The eyeball axial length and focusing power increase lightly and often has no pathological lesions (retinal degeneration, cornea, sphere lens…)
Evaluation school myopia: there are various methods of determining the school myopia: subjective test (Dondes), retinoscope and autorefractor This study uses autorefractor: Eyes are regarded as myopic when measured by the autorefractor after reducing accommodation is ≥ - 0.50 D
1.1.2 Status of the current school myopia
Issue on school myopia has studied only around 70 years of the nineteenth century Earlier, myopia was considered a genetic disease and malignant progression, therefore myopia was considered a disease without prevention and treatment The World Health Organization estimates that there are 2.3 billion people have refractive errors nowadays In which myopia is the first reason for vision loss and blindness (greater 2 times than the blindness caused by cataracts)
In Vietnam, school myopia is a public health concern because of a large number of people has myopia which affected their learning, quality of life and social - economical development Approximately 15% to 20% of students in urban schools have myopia and even it is higher in some big cities A research in 16 schools in
2008 in Thai Nguyen showed that the rate of myopia accounted for 73.09% of total refractive error The prevalence of school refractive in the city is 16.48% and 6.11% in rural areas
1.2 The risk factors of school myopia
There have been many studies on the risk factors leading to school myopia Factors can be classified into risk groups as follows:
- The risk factor of family characteristics, congenital and hereditary: family history has people with myopia
- The risk factor of school sanitation and hygiene practices: lack of lighting, over or under size of tables and chairs, incorrect practices in learning hygiene
Trang 7- The risk factors of near vision prolongation: high-intensity learning, learning pressure, playing game, less time for far looking, less outdoor activities and limited vision
- The risk factor of school myopia prevention is not good enough: the awareness of eye care in schools is not enough attention, the quality of medical activities is insufficient, most students do not have routine eye exam, week cooperation between sectors and levels of work-related health care for students
- Some other risk factors: lack of sleep, nutrition, ethnic groups and educational level The lack of understanding of myopia, risk factors and preventions is also an important factor contributing to the increased incidence and severity degree of myopia
1.3 Some solutions to prevent myopia school
There have been many studies and prevention measures for school myopia in the world and Vietnam There are three stages in intervention to prevent school myopia; however, in most localities in our country only implements Phase 1 Currently, Vietnamese eye institute actively deploys interventional activities in Phase 2 Many provinces have actively implement school myopia preventive activities such as Hanoi, Ho Chi Minh City, Hai Phong, Nam Dinh, Ninh Binh, Thai Nguyen, Hue, Da Nang, Ha Tinh These activities has received support and facilitate of the ministries and society
Many local and international organizations have supported for school myopia prevention and intervention by positive activities such as Rang Dong Corporation (RALACO), the Vietnam Urban Lighting , the Vietnam education and health care communities, school equipment companies in Vietnam, Project Management of Public Lighting in Vietnam (VEEPL), the World Health Organization (WHO ), the Organization for International Prevention of Blindness (IAPB), the UN Children's Fund (UNICEF), Christoffel Blindenmission Organization (CBM), the Atlantic Philanthropies (AP), the Fred Hollows Foundation (FHF), The First Sight, ORBIS International (OI)
Trang 8Chapter 2: SUBJECTS AND METHODS 2.1 Subjects
Secondary students in Midlands region of Thai Nguyen, parents, secondary school administrators, head teachers, school health personnel, facilities and sanitary conditions of school: tables, chairs, light
2.2 Time and place of study
- Study period: from 11/2006 to 12/2008
- Location of research: the study was conducted in four schools in the midland regions of Thai Nguyen province including: Phu Xa, Tan Thanh, Quyet Thang, Hoa Thuong secondary schools
2.3 Research methodology
2.3.1 Study Design: Using 3 types of research design as follows:
- Descriptive studies, cross-sectional design to determine the rate of school myopia
- Case-control study to identify a number of risk factors for myopia in secondary school students
- Intervention study with community and clinical intervention
2.3.2 Sample size and sampling technique
* Sample size for the descriptive studies: (21 /2) 2
) (
) 1 ( p
p p
* Sample size for case-control studies:
2
* 2 1
1 ) 2 / ( 2
)1(
)1(/1)1(/1
ε
α
−
−+
PP
Zn
The sample size is calculated based on the percentage of students with low bowed head when learning It is estimated for the control group 20% and OR = 2 with the expected accuracy of the OR was 0.35 As the sample size for each group are 223 students, rounded to 240 students Select the ratio of case/control is 1/2 Thus the sample size for case groups are 240 students and the control group are 480 students
Trang 9The case group inncludes students identified as myopic from -0.50 D to 6.00D as measured by autorefractor after dropping cyclogyl Using single randomized method selects 240 students from the list of myopia students of descriptive study
≤-Control group includes students with normal health status; emmetropia, similar to the case group on age, sex, school and class grade following the rate: 1 case and 2 controls
* Sample size for the study intervention:
- Sample size:
The sample size is calculated based on the estimated the ratio of myopia 17.42% and desire to reduce to 7.5% with α = 0.05, β = 0.2 The sample size for each group are 173 students
Due to the intervention study is conducted in 2 years, to ensure that studied subjects are continually monitored, this study is conducted on students grade 6 and
7 of the secondary schools, then randomly assigned 2 schools in the intervention group and 2 schools in the control group by lottery method, the results are as follows:
- Intervention group 1 (community intervention): students grade 6 and 7 of Tan Thanh secondary school
- Interventions group 2 (community combined treatment intervention): students grade 6 and 7 of Phu Xa secondary school
- Control group: students grade 6 and 7 of Quyet Thang and Hoa Thuong secondary school
As student’s grade 6 and 7 of those schools are more than calculated sample size therefore all students were selected in the sample
2.3.3 Content intervention
2.3.3.1 Intervention 1: Community intervention
- Forming the working group of myopia prevention in the interventional schools
- Communicating information on school myopia, myopia prevention measures for students, parents and teachers
2 2 1
2 2 1 1
2 1 2 / 1
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pp
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Zn
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Trang 10- Fixing Ergonomics: discussing how to fix, set up the standard of furniture, lighting, chalk board Mobilizing the contribution of parents to ensure hygiene in learning
- Medical intervention: the head of schools together with leaders of the local to strengthen and promote the school health department and local health services for early detection of school myopia
2.3.3.1 Intervention 2: Community and clinical interventions
Conclude the intervention 1 following measures:
- Wearing glasses: guiding myopia students used correct glasses and appropriate time to wear (wearing glasses when looking up the chalk board, while traveling; put off glass when using near eyesight)
+ Using eye drops to reduce accommodation: solution Correctol 2% x 4 times daily
- Guiding the parents and students added vitamin A from foods in their diet daily 2.3.4 The study variables
* Status of school myopia:
- The rate of myopia by school, grade (grade 6,7,8,9), by gender
- Percentage of students with visual impairment in levels: reduced, decreased or blind
- Percentage of students with mild, moderate and severe myopia
- Percentage of myopia in one or two eye
- Percentage of students already had glasses before investigated and the incident of myopia
* Risk factors for schools myopia:
- Classrooms’ sanitation: lighting system, lighting intensity, chalk board size and the size of tables and chairs
- The relationship between light intensity with school myopia
- The relationship between the size of chairs and school myopia
- The relationship between learning posture and school myopia
- The relationship between the home learning place and school myopia
- The relationship between the intensity of class learning and home learning and school myopia
Trang 11- The relationship between the times spent on leisure activities with near vision and school myopia
- The relationship between the knowledge of students and parents and school myopia
- The association of family history and school myopia
- The relationship between school health activities with school myopia
* Effectiveness of interventions:
- The number of sessions that students and parents were communicated about school refraction
- The number of classrooms were repaired Ergonomics
- The number of students worn glasses and taken medication to prevent myopia progression
- The ratio of myopia before and after the intervention in the intervention group 1,
2 and control groups
- The incidence of school myopia in intervention groups 1, 2 and control groups
- The degree of myopia and progression of myopia between the intervention groups
1, 2 and control groups: decreased, stable or increased in dioptre
- The efficiency and effectiveness of the intervention measurements, comparisons between the intervention and non-intervention
2.4 Methods of collecting information
2.4.1 Diagnose for myopia
- Test visual acuity using Landolt chart: test all students to identify students with visual impairment Assessment the visual acuity by the classification of the World Health Organization:
+ Visual acuity above 7/10: Normal
+ Visual acuity from 3/10 to 7/10: Decrease
+ Visual acuity from count finger at 3m to VA 3/10: Highly decrease
+ Visual acuity <cont finger at 3m: Blind
- Diagnoses myopia: the students had visual impairment examined by autorefractor with cyclogyl 1% eye drop Eyes are regarded as myopic as myopia degree above 0.50D when measured by autorefractor after dropping cyclogyl
2.4.2 Measuring classroom’s hygiene index:
- Illuminate coefficient is evaluated based on "Regulations on school hygiene" by the decision No 1221/2000/QD-BYT of the Minister of Health issued 18 April
Trang 12- The intensity of illumination in the classroom: measured by Luxmeter made in Japanese Evaluated criterion: 100-300 lux: standard, <100 lux: under standard
- Tables and chairs dimensions: measuring the height, length and width of tables and chairs with millimeters Then the difference between tables, chairs and student’s build are compared
- Dimension of chalk board and on high hanging: the length and width of chalk board and the length hanging up are measured
2.4.3 Interview:
Students and parents are direct interviewed by questionnaires about the intense
of learning, time for leisure activities with near vision such as reading, watching television, playing video games and knowledge of school myopia and preventive measurements Knowledge of students and parents are evaluated based on the correct answers on the questionnaire form, each correct answer is counted as 1 point Based on the cut off 75% of the total score, divides practical knowledge into
2 levels: Good: ≥ 75% of the total points; Not good: < 75% of the total points 2.4.4 Observation:
To observe student learning posture and assess as follows:
- Low head bowed: The distance from the eye to notebook less than 25 cm
- Correct sitting posture: The distance from the eye to notebook ≥ 25 cm
2.4.5 Discussion group:
Forming 3 focus groups of administrators, school health personnel, representative of head teachers and representative of parents that discuses in focus 2.4.6 Monitoring interventions
Intervention activities are monitored directly by PhD fellow, monitoring monthly and when the school organizes media communication and parent meetings 2.5 Methods of data processing:
SPSS 18.0 software with algorithms biostatistics is used in this study The results which compared before and after intervention are tested statistically (p
<0.05) and evaluated by effective indicators and interventional indicators
2.6 Measures to control error
Avoid using subjective methods to diagnose myopia in order to avoid false myopia cases Using autorefractor identifies myopia
Trang 13Chapter 3 FINDINGS 3.1 The situation of school myopia in secondary school in Midlands region of Thai Nguyen province
Table 3.3 The rate of school myopia in 4 schools
students
>0.05
Comment: There was no significant difference in the ratio of myopia among 4 investigated schools (p> 0,05) School myopia rate was 16.8% on average
Table 3.4 The rate of school myopia following class grade
investigated
Number myopia students
Chart 3.1 Myopia rate by gender and by class grade