Effect of orbital decompression on diplopia in thyroid-related orbitopathy.

Purpose: To determine the incidence of new-onset diplopia and evolution of preexisting diplopia in patients with thyroid-related orbitopathy undergoing orbital decompression surgery.

Methods: A retrospective chart review was conducted of patients who had undergone orbital decompression for thyroid-related orbitopathy between 1999 and 2008 in one of the authors' practice (D.J.). A total of 217 orbits in 123 patients were identified. The clinical indication for decompression surgery (i.e., exposure keratitis, optic neuropathy, or improvement of cosmesis) was recorded in each case, as was the presence of pre- and postoperative diplopia. The surgical technique (1-, 2-, or 3-wall decompression) was noted for each patient.

Results: Review of the charts of patients who underwent orbital decompression surgery for thyroid-related orbitopathy revealed a preoperative prevalence of diplopia of 26% and a postoperative prevalence of 40.7%. Amongst the patients with preoperative diplopia (n = 32), 28.1% (n = 9) had complete resolution of their diplopia after decompression, while 65.6% (n = 21) remained stable and 6.3% (n = 2) worsened. The incidence of new-onset diplopia was 29.7% in this case series of orbital decompression using a transcaruncular and swinging eyelid approach for medial wall and strut-sparing floor decompression. Rates of new-onset diplopia were significantly higher when periorbita was opened (40.0%, n = 82) compared with when it was left intact (11.8%, n = 37) CONCLUSIONS:: It has previously been reported in the literature that orbital decompression for thyroid-related orbitopathy can cause diplopia in a significant number of cases. This provides the rational for performing orbital decompression prior to strabismus surgery in the management of thyroid-related orbitopathy. In this case series, the authors noted resolution of diplopia in a significant proportion (28.1%) of patients with preexisting diplopia. This is rarely commented on in other articles but is important in the preoperative discussion. An incidence of new-onset diplopia of 29.7% was identified. Opening the periorbita was associated with an increased incidence of new-onset diplopia.