Resolution of hypertropia with correction of intermittent exotropia

Purpose We describe the spontaneous resolution of hypertropia in a subset of patients with preoperative exotropia and hypertropia, who underwent surgery for intermittent exotropia alone. Design This was a retrospective case series. Methods The charts were reviewed of 17 patients who underwent surgical correction for an intermittent exotropia, who additionally were noted on preoperative exam to have greater than 5 prism dioptres of vertical deviation in primary position. Patients were excluded if they had prior strabismus surgery, dissociated vertical deviation, and paretic or restrictive deviations. Results All patients were documented to have complete resolution of any vertical deviation in any field of gaze. This effect was noted to persist. Conclusions We propose that the measured distance hypertropia, which is coincident with intermittent exotropia, even with the appearance of superior oblique dysfunction or inferior oblique overaction, is not created by a true vertical or cyclovertical muscle imbalance. Further, that the reduction of the hypertropia at near fixation predicts its resolution with horizontal muscle surgery. Therefore, vertical surgery should not be performed to address the coincident vertical deviation in these patients.