AIM: To observe the clinical effect of super quantity of binocular medialrectus in treating large angle concomitant esotropia.

METHODS: Eighty-one patients with large angle concomitant esotropia were analyzed retrospectively. According to the operation method, they had been divided into observation group(large recession of rectus muscle)and control group(normal recession of rectus muscle). The number of muscle were evaluated, eye's position and involution function in a week and a year after operation were also evaluated.

RESULTS:Forty-three cases in observation group had binocular medial rectus treatment, while 5 cases had binocular medial rectus+monocular medial rectus muscle resection treatment. Six cases in control group had the surgical treatment of bilateral medial rectus recession, 21 cases had binocular medial rectus+monocular medial rectus muscle resection and 6 cases with binocular medial rectus+bilateral lateral rectus shortening. The difference of the muscles' numbers of two groups in operation had statistical significance(χ²=41.72, P<0.01). One week after the operation, eye position of observation group was -2^△～+12^△, the average was +6.52^△±3.23^△, while that of control group was -3^△～+10^△, the average was +5.38±2.46^△. The difference of two groups had no statistical significance(t=1.45, P=0.08). One year after operation, eye positions of observation group and control group were -5^△～+10^△(average: +4.57^△±2.71^△)and -5^△～+8^△(average: +3.92^△±2.15^△). The difference of two group had no statistical significance(t=1.23, P=0.10). One week after the operation, 14 cases of observation group and 6 cases of control group's involution function were limited. One year after operation, 5 cases of observation group and 2 cases of control group's involution function were limited. The differences of two group had no statistical significance(χ²=1.27, P>0.05; χ²=0.47, P>0.05).

CONCLUSION: Super quantity of medial rectus recession in treating large angle concomitant esotropia can reduce the muscle's number, but it has no obvious influence on eyeball's involution function.