| Myopia is a refractive defect of the eye in which collimated light produces image focus in front of the retina when accommodation is relaxed. Amongst all the strata of age, prevalence rate of myopia in school children is the highest, which, for the worse, keeps mounting.Although it is still unclear that which are the definite causes of the disorder, experts maintains that shortsightedness usually results from genetic, developmental, environmental factors and/or a mixture of above all. Among these, near-work activities are deemed the most paramount external risk factors, which is evaluated by such parameters as time of reading (or other near-work activities including watching TV, using computer, etc.) and environmental factors (e.g. illumination intensity). Besides, eating habits are indirect external factors of myopia as well.Purpose:To explore probable risk factors associated with juvenile myopia, and to determine prevalence of myopia among school children by means of cross-sectional investigation, refractive examination and data analysis.Objects:A total of 6531 students (age 6～16) in one of the four primary schools, four middle schools and one nine-year-consistent-system school of Xuhui District in Shanghai, China were enrolled.Methods:A questionnaire survey and a refractive examination were adopted. The questionnaires were given out and gathered by healthcare teachers of each school. For senior students they were filled out by themselves; for junior, by children's parents after a parents meeting hold by their class teacher. Visual and optical examinations were conducted by ophthalmologists, from Eye and Ear Nose Throat (EENT) Hospital affiliated to Fudan University, bringing related equipments for measure to schools. Data of collected questionnaires and examination results were pooled and analyzed with software (SPSS).Results:1. Statistically analyzed the collected 6465 questionnaires,13 of all the eye-utilizing habits and life style related indexes were statistically significant among different age groups. Age had a positive correlation with such indexes as time-of study after school, of gazing at screens (TV and Computer) within the term, of gazing at screens during vacations (winter or summer), and of daily out-door activities-, proportion-of standard way of holding a pen, posture of writing, eye-book distance -and population of reading in bed, during walk or taking a bus; while a negative one with time in bed and regular life style. In addition,8 of all indexes were evidently associated with gender. More boys tended to maintain standard writing postures, to spare more time on after school study or screens within terms, to eat more flesh and not to read during walk or taking buses; whereas girls were prone to bear more knowledge of using and protecting eyes in mind, to spend less time on screens during vacations and to eat more fruits and vegetables than their male peers.2. Prevalence of myopia in the whole objects was 50.4%, in junior 43.3%, in senior 70.8%. The senior's visions on average were poorer than the junior's (p<0.01); girls'slightly worse than boys', though without statistical significance.3. Statistics showed that degree or severity of juvenile myopia were associated with these factors:reading posture, eye-book distance, reading while moving, time of study after school, time on screens, rhythm of life style and time in bed.Conclusions and suggestions:1. Most of these junior and senior school students had failed to develop correct reading and writing habits. Though the majority of the investigated children knew about ABCs of eye-using, few interpreted them into daily action. It was indicated that teachers and parents should have put more emphasis on monitoring children's behavior of utilizing eyes in stead of cramming them with theories only.2. Prevalence of myopia in Xuhui District was almost at the same level of that in Shanghai, and was higher than that in China. As age increased, vision decreased; girls' vision poorer than boys'. If define diopters>=0.00D as normal, then 0.00D～-3.00D (included) would be mild myopia; -3.00D～-6.00D (included), moderate; and<-6.00D, severe (if one had different vision acuities between the two eyes, adopt the poorer one as his/her vision status). According to this diagnose standard and classifications, the prevalence would be 87.7%. However, since there had been no similar study reported in China, this investigation failed to have a compare.3. Pathogen of myopia, as a complex, is affected by comprehensive risk factors. This study evidenced that age, gender and Eye-book distance were the major ones. We had best incorporate integrated policies and strategies into prevention of juvenile myopia. |
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