Discipline of Orthoptics, Faculty of Health Sciences, University of Sydney, Sydney, NSW, Australia.
Ophthalmology. 2013 Oct;120(10):2100-8. doi: 10.1016/j.ophtha.2013.02.035. Epub 2013 May 11.
To examine the risk factors for incident myopia in Australian schoolchildren.
Population-based, longitudinal cohort study.
The Sydney Adolescent Vascular and Eye Study (SAVES) was a 5- to 6-year follow-up of the Sydney Myopia Study (SMS). At follow-up, 2103 children were reexamined: 892 (50.5%) from the younger cohort and 1211 (51.5%) from the older cohort. Of these, 863 in the younger cohort and 1196 in the older cohort had complete refraction data.
Cycloplegic autorefraction (cyclopentolate 1%; Canon RK-F1; Canon, Tokyo, Japan) was measured at baseline and follow-up. Myopia was defined as a spherical equivalent refraction of ≤-0.50 diopters (D). Children were classified as having incident myopia if they were nonmyopic at baseline and myopic in either eye at follow-up. A comprehensive questionnaire determined the amount of time children spent outdoors and doing near work per week at baseline, as well as ethnicity, parental myopia, and socioeconomic status.
Incident myopia.
Children who became myopic spent less time outdoors compared with children who remained nonmyopic (younger cohort, 16.3 vs. 21.0 hours, respectively, P<0.0001; older cohort, 17.2 vs. 19.6 hours, respectively, P=0.001). Children who became myopic performed significantly more near work (19.4 vs. 17.6 hours; P=0.02) in the younger cohort, but not in the older cohort (P=0.06). Children with 1 or 2 parents who were myopic had greater odds of incident myopia (1 parent: odds ratio [OR], 3.2, 95% confidence interval [CI], 1.9-5.2; both parents: OR, 3.3, 95% CI, 1.6-6.8) in the younger but not the older cohort. Children of East Asian ethnicity had a higher incidence of myopia compared with children of European Caucasian ethnicity (both P<0.0001) and spent less time outdoors (both P<0.0001). A less hyperopic refraction at baseline was the most significant predictor of incident myopia. The addition of time outdoors, near work, parental myopia, and ethnicity to the model significantly improved the predictive power (P<0.0001) in the younger cohort but had little effect in the older cohort.
Time spent outdoors was negatively associated with incident myopia in both age cohorts. Near work and parental myopia were additional significant risk factors for myopia only in the younger cohort.
FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.
研究澳大利亚学龄儿童近视发生的危险因素。
基于人群的纵向队列研究。
悉尼青少年血管与眼部研究（SAVES）是悉尼近视研究（SMS）的 5 至 6 年随访研究。随访时，重新检查了 2103 名儿童：年轻队列 892 名（50.5%），年长队列 1211 名（51.5%）。其中，年轻队列有 863 名，年长队列有 1196 名有完整的屈光数据。
在基线和随访时使用睫状肌麻痹自动验光仪（环戊酮 1%；佳能 RK-F1；佳能，东京，日本）进行测量。近视定义为等效球镜度数≤-0.50 屈光度（D）。如果儿童在基线时为非近视，而在随访时双眼均近视，则被归类为发生近视。一个全面的问卷确定了儿童在基线时每周户外活动和近距工作的时间，以及种族、父母近视和社会经济地位。
近视发生。
发生近视的儿童户外活动时间明显少于未发生近视的儿童（年轻队列分别为 16.3 小时和 21.0 小时，P<0.0001；年长队列分别为 17.2 小时和 19.6 小时，P=0.001）。发生近视的儿童进行的近距工作明显更多（年轻队列为 19.4 小时与 17.6 小时，P=0.02），但年长队列中无差异（P=0.06）。有 1 名或 2 名近视父母的儿童发生近视的可能性更高（1 名父母：优势比[OR]，3.2，95%置信区间[CI]，1.9-5.2；双亲：OR，3.3，95% CI，1.6-6.8），这种情况在年轻队列中更明显，而在年长队列中不明显（P<0.0001）。东亚裔儿童的近视发病率明显高于欧洲白种人（均 P<0.0001），且户外活动时间明显较少（均 P<0.0001）。在基线时较低的远视屈光度是近视发生的最显著预测因素。将户外活动时间、近距工作、父母近视和种族纳入模型，可显著提高年轻队列的预测能力（P<0.0001），但对年长队列影响较小。
在两个年龄组中，户外活动时间与近视发生呈负相关。近距工作和父母近视是近视的额外显著危险因素，仅在年轻队列中如此。
