Conclusion:Symmetric recession of internus in alternative esotropia can improve the success rate and the binocular vision function.

交替性斜视手术采用同直肌后徙术，不但手术成功率高，而且有利于手术后双眼三级功能建立。

Objective To study the optimal time for operation of intermittent exotropia, so that we can orthopia strabismus and attain normal binocular function.

目间歇性外斜视最佳手术时机，以求达到矫正斜视并获得完善双眼单视功能目。