Effects on horizontal deviations in primary position of tenotomy combined with myectomy of inferior oblique muscle

Objective To evaluate the effect of the inferior oblique muscle tenotomy combined with myectomy on horizontal deviations in primary position.Methods From January 2012 to March 2013,6l cases (68 eyes) underwent tenotomy combines with myectomy of inferior oblique muscles as the sole without medial muscles surgery.Of the 61 patients,54 had unilateral inferior oblique muscle surgery,and then 7 had bilateral surgeries.Followed up for three to twelve months,and investigated the changes of horizontal deviations with the primary position after procedures as well as the relationship between the changes and preoperative horizontal deviations.Results 1.The changes angle of horizontal near deviation:There were 53 eyes (53/68,77.94％) esoshift after procedures,changed 3～25 △,(6.58±4.05)△,The comparison of angle of strabismus showed significant difference pre-and post-operation (t =4.945,P ＜0.001).Nine eyes (9/68,13.24％) exoshift 2～5 △,(3.71±0.97) △,showed no difference pre-and post-operation (t =1.906,P =0.093).Six eyes (6/68,8.82％) had no alteration of the deviation in primary position.2.The changes angle of horizontal distance deviation:There were 50 eyes (50/68,73.53％) esoshift,changed 2～20△,(6.34±3.25)△,The comparison showed significant difference pre-and post-operation (t =4.911,P ＜0.001).There were 12 eyes (12/68,17.65％) exoshift 1～5△,(2.33 ±1.57)△,showed no difference pre-and post-operation (t =1.798,P =0.100).Six eyes (6/68,8.82％) had no alteration of the deviation in primary position.3.There was positive correlation between the change and preoperative horizontal deviations (r 1＝0.519,P 1＜0.001; r 2=0.400,P 2=0.002).Conclusions The inferior oblique muscle tenotomy combined with myectomy can affect the horizontal deviations in primary position.