| Objectives To investigation the epidemiologic characteristics of primary and secondary school students and light environment at Zhaohui district, especially to obtain To examine the prevalence of refractive error and distribution of ocular biometric parameters, and the determinants in myopia development.Include:2169pimary school students,928secondary school students,1496boys,1601girls,age6-15years old.Method:1.Cluster sampling method, the Zhaohui District elementary and middle school students (n=3097) were given the standard visual acuity examination, detecting diopter and corneal curvature under non-cycloplegic pupil with automate optometry instrument, axial length of the eye with IOL master. Diagnostic criteria for myopia:any one eye"s spherical equivalent power<=-0.5, naked-eye vision<20/30.2. Investigation by questionnaire against primary students on the topic of time spent on reading and studying and exposure to light, questions including subject’s age, birthday gender, refractive status of subject’s parents, type of lamp used for studying, whether sleep with room lighting, time spent on outdoor-extracurricular activities, time spent on reading and studying after school, time spent on watching TV and using computer, the use of projector in classroom, the lighting in classroom in daytime, time spent on outdoor activities and studying in weekends. 3. The data collected and the result were inputted with a format in Excel, and a data base is established. SPSS17.0software was used in the analysis.Result:1The prevalence of myopia in primary and secondary students was47.56%, which34.25%in primary students and78.64%in secondary students respectively. This prevalence increases with the time of studying in school, and2increases with significant amplitude were found. The prevalence increases from17.88%to32.87%, which was found in the progress of primary2students to primary3; another increase in the prevalence, from50.77%to74.91%, was found in the progress of primary5students to primary6. The increase of the myopia prevalence was stable after that. Girls had a higher prevalence (48.53%) than boys (46.52%).2. The average spherical equivalent power of the primary and secondary students was (-1.74±1.95) D, and the average axial length was (23.84+1.40) mm, and the average corneal curvature was (43.34+1.53) D. The spherical equivalent power and the axial length increase with ages, which were more rapidly in primary students, while the corneal curvature stays stable. There was an obvious relationship between the spherical equivalent power and the axial length (r=-0.6, P=0.000), while the relationship between the spherical equivalent power and the corneal curvature was not obvious (P=0.059).There is a (P<0.05) in all Average spherical equivalent power, Average axial length, and Average corneal curvature mentioned above, both in boys and girls.3. In multilevel regression models:it was found that spent on outdoor-extracurricular activities, the lighting in classroom in daytime, time spent on outdoor activities and studying in weekends, extra-tutorial class and some other factors shown a significant influence in the development of myopia statistically.(P<0.05).Conclusion:1.The prevalence of myopia is relatively higher in students studying in primary and middle school students, and there is a trend of increasing with the academic progress.2.Rapid increases in myopic progression and axial length were found in primary students. 3.Girls have a higher prevalence of myopia and also a higher myopic power.4.Extensive near tasks, lack of outdoor activities and over-exposure to artificial lighting may be the major factors inducing myopia. |
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