Resolution of hypertropia with correction of consecutive horizontal deviation

To study the resolution of hypertropia in patients who undergo horizontal deviation surgery for consecutive esotropia or consecutive exotropia.

We retrospectively reviewed the records of 23 patients with consecutive esotropia or exotropia who had concomitant vertical tropia. All patients had had surgery for horizontal deviation that required further surgery to correct consecutive horizontal strabismus and had a minimum of six months of postoperative follow-up. All patients were noted to have vertical deviation greater than 5 prism diopters (PD) in primary position on preoperative examination. Patients underwent corrective surgery for horizontal strabismus without surgical manipulation of the vertical extraocular muscles. The exclusion criteria were coexisting oblique muscle dysfunction, manifest or latent dissociated vertical deviation, and extraocular muscle palsy.

The mean preoperative vertical deviations were 7.6 ± 2.3 PD for distance and 7.3 ± 2.3 PD for near. All patients had resolution of vertical deviation in all fields of gaze despite surgical correction only being made to horizontal extraocular muscles. No patients had measureable vertical tropia during six months of follow-up.

We propose that measureable hypertropia unrelated to oblique muscle dysfunction, dissociated vertical deviation, or paretic/mechanical muscle that coincides with consecutive horizontal deviation can be resolved with horizontal muscle surgery alone. Therefore, it may not be necessary to perform vertical surgery to correct coincident vertical deviation in patients with consecutive horizontal deviation. More research is needed in the form of prospective clinical trials to determine whether vertical surgery has any utility for these patients.