AIM: To evaluate the correction of inferior oblique anterior transposition(IOAT)in the treatment of bilateral superior oblique paralysis with inferior oblique overaction(IOOA).

METHODS: Totally 28 patients with bilateral IOOA underwent equal bilateral IOAT; the horizontal deviation was corrected at the same operation. The amount of vertical deviation in primary position and inferior oblique overaction pre-operation and post-operation was measured. Curative effects of surgical method were analyzed.

RESULTS: For 26 patients with vertical deviations in primary position in the range of 15^△-25^△, clinical effect of cure was observed with disappearance of head position. Vertical deviations in primary position decreased from >25^△to 7.8^△ for the patient who underwent bilateral IOAT combined with contralateral inferior rectus recession. Head position was improved and IOOA was eliminated for all patients with no eye movement restriction after surgery.

CONCLUSION:IOAT is an effective method for correcting large vertical deviation in patients of bilateral superior oblique paralysis with IOOA, especially in elimination of unequal bilateral IOOA. It has the advantage of easy to operating, low recurrence and effective.