The Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China.
Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
Clin Exp Optom. 2020 Mar;103(2):177-183. doi: 10.1111/cxo.12980. Epub 2019 Oct 31.
The aim of this study was to investigate the prevalence of myopia in key (university-oriented) and non-key elementary schools in China using a traditional and a new criterion for myopia diagnosis in an epidemiological study.
This school-based, cross-sectional study examined students from four key schools and seven non-key schools. Non-cycloplegic autorefraction and visual acuity (VA) were performed on each student. Myopia was defined as a spherical equivalent (SE) refractive error not better than -1.00 D. A questionnaire was also administered.
Of the 13,220 students examined, 6,546 (49.5 per cent) had myopia using the criterion of SE not better than -1.00 D. However, 2,246 (34.3 per cent) of these myopes had VA ≥ 0 logMAR in both eyes, indicating they were not functioning as myopes. Thus, a second myopia criterion was adopted: SE refractive error not better than -1.00 D + uncorrected VA ≥ 0 logMAR in at least one eye. By this definition, only 32.5 per cent of the overall sample had myopia. Students in key schools had a higher prevalence of myopia than those in non-key schools (53.8 per cent versus 44.7 per cent) by the initial criterion. By the new criterion, the prevalence of myopia was 41.2 per cent versus 22.7 per cent. Myopia was equal in grade 1 of both school types, but accelerated faster in key schools, where there was a much higher prevalence of myopia by fourth grade, and continued up to 79.2 per cent prevalence by sixth grade based on SE refractive error not better than -1.00 D.
Students in more competitive university-oriented elementary schools developed myopia much faster than those in regular schools, although they started with the same level of myopia. Since one-third of the 'myopes' had VA ≥ 0 logMAR in both eyes, they would not be prescribed a correction, or be clinically treated as myopes. A new criterion of SE refractive error not better than -1.00 D + uncorrected VA ≥ 0 logMAR in at least one eye was tested. This criterion is more clinically appropriate and could be used in future epidemiological studies.
本研究旨在通过一项流行病学研究，使用传统和新的近视诊断标准，调查中国重点（以大学为导向）和非重点小学的近视患病率。
本项基于学校的横断面研究检查了四所重点学校和七所非重点学校的学生。对每个学生进行非睫状肌自动折射和视力（VA）检查。近视定义为球镜等效（SE）屈光不正不低于-1.00 D。还进行了问卷调查。
在检查的 13220 名学生中，使用 SE 不低于-1.00 D 的标准，有 6546 名（49.5%）患有近视。然而，其中 2246 名（34.3%）近视者双眼 VA≥0 logMAR，表明他们并未发挥近视的作用。因此，采用了第二个近视标准：SE 屈光不正不低于-1.00 D+至少一眼未经矫正的 VA≥0 logMAR。根据该定义，只有 32.5%的总体样本患有近视。根据初始标准，重点学校学生的近视患病率高于非重点学校学生（53.8%比 44.7%）。根据新的标准，近视患病率为 41.2%比 22.7%。两种类型学校的一年级学生近视程度相同，但重点学校的近视进展更快，到四年级时近视患病率更高，达到 79.2%，根据 SE 屈光不正不低于-1.00 D 计算。
在竞争更加激烈的以大学为导向的小学中，学生的近视发展速度比普通学校的学生快得多，尽管他们开始时的近视程度相同。由于三分之一的“近视者”双眼 VA≥0 logMAR，他们不会被处方矫正，也不会被临床诊断为近视。测试了 SE 屈光不正不低于-1.00 D+至少一眼未经矫正的 VA≥0 logMAR 的新标准。该标准更符合临床实际，可用于未来的流行病学研究。
