双眼开放视野自动验光仪与传统电脑验光仪的比较

Comparison between binocular, open-field auto ref/keratometer and conventional autorefractor

目的探讨睫状肌麻痹对双眼开放视野自动验光仪与传统电脑验光仪的测量结果差异的影响。方法连续收集北京同仁医院就诊的304位中小学生。对受试者分别在睫状肌麻痹前后进行传统电脑验光仪（Accuref-K9001，以下简称K9001验光仪）与双眼开放视野自动验光仪（WAM-5500，以下简称WAM验光仪）的客观验光。求得球镜、等效球镜（SE）与散光轴的符合率（定义为：度数相差≤0．50D，轴向相差≤20°）；根据两种验光仪SE的平均值与差值绘制Bland—Altman图并进行分布情况分析。结果睫状肌麻痹前，两种验光仪球镜、SE与散光轴的符合率分别为77．3％、78．6％与66．0％；睫状肌麻痹后相应的符合率增至为94．4％、95．1％与69．5％。睫状肌麻痹前两种验光仪SE的平均差值为0．12D，且与SE的平均值（睫状肌麻痹后）存在正相关关系（rpearson=0．21，P〈0．001）；睫状肌麻痹后sE的平均差值为-0．08D。K9001验光仪睫状肌麻痹前后自身SE差值较WAM验光仪大（0．51D与0．31D，P〈0．001）。睫状肌麻痹前两种验光仪sE差值的分布情况为：WAM较K9001偏负0．25D以上（1组）的共51例（16．8％），差异在0．25D以内（2组）的共160例（52．6％），WAM较K9001偏正0．25D以上（3组）的共93例（30．6％）。睫状肌麻痹后，1组共69例（22．7％），2组增至213例（70．1％），3组减少至22例（7．2％）。结论双眼开放视野自动验光仪较传统电脑验光仪测量值偏正。开放视野验光仪能在一定程度上减少仪器性近视，在临床筛查与科研领域将具有更广阔的应用前景。

Objective To compare the refractive results between open-field auto ref/keratometer and conventional autorefractor, and to investigate the effect of cycloplegic to this difference. Methods Three hundred and four primary and secondary school students were consecutively enrolled in Beijing Tongren Hospital. Non-cycloplegic and cycloplegic objective refractions were performed for each subject by conventional autorefractor （Accuref-K9001, Shin Nippon, Japan） and binocular, open-field auto ref/ keratometer （Grand Seiko Co. , Ltd. , Hiroshima, Japan ）. The coincidence rate of sphere, spherical equivalent （SE） and axis （defined as difference of diopter ≤0. 50 D, difference of axis degree ≤ 20°） were calculated; Bland-Altman and distribution analysis were performed according to mean and difference of SE. Results The coincidence rate of sphere, SE and axis were 77.3% , 78.6% and 66. 0% before cycloplegic and increased to 94. 4% , 95.1% and 69.5% after cycloplegic, respectively. The difference （95% Cl） of SE before cycloplegic between these two refractometers was 0. 12 （ - 1.04 to 1.29 ） D and was positively correlated with the mean of SE （after cycloplegic） （rpearson=0. 21, P 〈0. 001 ）. The difference （95% CI） of SE after cycloplegic was - 0. 08 （ - 0. 60 to 0.45 ） D. The difference （ 95% CI） of SE of K9001 autorefractor before and after cycloplegic was larger than that of WAM autorefractor [ 0. 51 （ - 0. 83 - 1.84） D and 0. 31 （ - 0. 66 to 1. 28 ） D, P 〈 0. 001 ]. Before cycloplegic, SE measured by WAM autorefractor showed myopic more than 0. 25 D than K9001 （ group 1 ） was found in 51 （ 16. 8% ） subjects; difference within 0. 25 D was found in 160 （52. 6% ） subjects; hyperopic more than 0. 25 D （group 3） was found in 93 （30. 6%） subjects. After cycloplegic, 69 （22. 7%） subjects were found in group 1, and subjects increased to 213 （70. 1% ） and decreased to 22 （7.2%） in group 2 and group 3, respectively. Conclusion The binocular, open-field auto ref/keratometer provides more hyperopic readings than conventional autorefractor. It will be useful in both clinical screening and scientific research because it produces less instrument myopia than that of conventional autorefractor.