Residual diplopia after repair of pure orbital blowout fracture: The importance of extraocular muscle injury

Background: The aim of this study was to evaluate the incidence of and possible risk factors for residual diplopia after surgical repair of pure blowout fracture (BOF) of the orbit. Methods: Sixty-three patients with pure orbital BOFs who had preoperative symptomatic diplopia were investigated. In each patient, the relationship of residual diplopia and the following factors were analyzed: (1) timing of surgery, (2) presence of enophthalmos, (3) site of fracture, (4) type of fracture, (5) extraocular muscle swelling, and (6) surgical method. Results: Fifty-five (87.3%) of 63 patients experienced improvement in diplopia and 8 (12.7%) patients had residual symptomatic diplopia after surgery. Of the six factors, only swelling of extraocular muscle on computed tomography (CT) scan was significant for the development of residual diplopia after surgery (p < 0.01). Conclusion: In pure BOF of the orbit, patients who have swelling of the extraocular muscles on CT scan arc more likely to have residual postoperative diplopia.