方法：前瞻性对照研究。选取15名正视眼志愿者入选本试验(年龄18～38岁，男6名，女9名)。利用偏光镜和液晶显示器的偏振特性，设置3种不同的注视方式：(1)右眼能看到屏幕显示的视标，左眼无法看到；(2)右眼无法看到屏幕视标，左眼能看到；(3)双眼均能看到屏幕视标。使用红外电脑验光仪分别测量注视距离为5、2、1、0.5、0.33m时的客观验光值(以等效球镜计算)，计算所有受试者在以上3种注视方式下的调节反应量。采用重复测量的方差分析和t检验比较不同注视方式下双眼调节反应的差异。

结果：采用注视方式(1)(2)时，双眼在各种调节刺激下产生的调节反应有明显差异，其中使用眼(能看到屏幕视标眼)的调节反应均比未使用眼(不能看到屏幕视标眼)大(P<0.05)。采用注视方式(3)时，各种调节刺激下的双眼调节反应无明显差异(P>0.05)。

结论：双眼开放状态下，经常被使用眼的睫状肌处于相对紧张状态，较少使用眼则处于相对放松状态。这种调节反应的不均衡性，很可能是促发近视发生的危险因素。

METHODS:Fifteen volunteers with emmetrope were recruited into this study(aged 18～38), 6 males and 9 females. Three different viewing conditions were set up by using polarizing glasses and liquid crystal display:(1)right eye could see the visual target on the screen, but left eye cannot see it;(2)left eye could see the visual target on the screen, but right eye cannot see it;(3)both eyes could see the target. Accommodative responses were measured by infrared auto-refractor when fixating at the target at 5, 2, 1, 0.5 and 0.33m under the above 3 viewing conditions. The differences of accommodative responses under different viewing conditions were compared by using variance analysis of repeated measuring and t test.

RESULTS:Significant differences of accommodative responses between the two eyes were found under condition(1)and(2)at all the fixating distance. The accommodative responses in used eyes which can see the visual target were higher than in non-used eyes which cannot see the visual target(P<0.05). No differences of accommodative responses were found under condition(3)at all distance(P>0.05).

CONCLUSION:Ciliary muscles in the used eyes were more relatively tonic than non-used eyes under binocular open viewing condition. The imbalance of accommodative responses between two eyes may be one of the risk factors resulting into the occurrence of myopia.