Strabismus after inferior-medial wall orbital decompression in thyroid-related orbitopathy.

PURPOSE To evaluate the rate and pattern of new-onset diplopia after inferior-medial wall orbital decompression in thyroid-related orbitopathy (TRO) patients. METHODS Medical records of TRO patients who underwent orbital floor and medial wall decompression at the Goldschleger Eye Institute, Sheba Medical Center between 1/1986 and 12/2007 were reviewed and analyzed. MAIN OUTCOME MEASURES primary- and down-gaze diplopia, strabismus (prism diopter [PD]). RESULTS Fifty-one TRO patients (30 females, mean age of 51 years) underwent 102 bilateral inferior-medial wall orbital decompressions. Preoperatively, 29 patients (57%) reported primary gaze diplopia. Of these, 13 patients (45%) had persistent or worsened diplopia postoperatively, all of which required strabismus surgery. Fifteen patients had no primary gaze diplopia preoperatively. Of these, five patients (33%) had new-onset diplopia postoperatively, and only one patient (7%) required strabismus surgery. No data regarding pre-existing diplopia were available in seven patients. Orbital decompression had a significant effect on horizontal ocular deviations with increasing esotropic shift. Primary position esotropia increased from 11.1 (± 22.5) PD preoperatively to 23.8 (± 20.5) PD after surgery (p = 0.01, paired samples t-test). No severe complications were encountered in this group of patients. CONCLUSIONS Inferior-medial wall orbital decompression is associated with a relatively high rate of new-onset diplopia of up to 33%. Patients with pre-existing primary and/or downgaze diplopia are more likely to have persistent symptoms postoperatively that may require strabismus surgery.