Diplopia after Isolated Inferior Orbital Wall Fracture According to the Computed Tomography Findings

Purpose: To investigate the postoperative changes in diplopia and evaluate factors that affect diplopia after isolated inferior orbital wall fracture. Methods: A retrospective study was conducted on 200 patients who underwent reconstruction surgery for isolated inferior orbital wall fracture between March 2001 and December 2020. Diplopia was categorized into peripheral, central, and full-degree types based on the history and binocular single vision. The natural course of diplopia was analyzed pre-operatively and at 1 day, 6 weeks, and 6 months postoperatively. We analyzed the orbital computed tomography images to determine fracture size (small, medium, or large), fracture site (anterior, middle, posterior, or mixed), extraocular muscle (EOM) size (swelling or deformity), EOM site (incarcerated or prolapsed), and EOM tenting. Results: Diplopia was seen in 144 out of 200 patients (72.0%) before surgery; peripheral diplopia was seen in 57 patients (39.6%), central diplopia in 46 (24.3%), and full-degree diplopia in 20 (13.9%). Pre-operative diplopia differed according to the pre-operative limitation of range of motion (LOM) (p < 0.001) and EOM site (p = 0.022). Pre-operative diplopia type differed according to the LOM direction (p = 0.018) and EOM size (p = 0.020). Diplopia persisted in 33 patients (16.5%) 6 months after the surgery. Recovery was faster in patients with peripheral diplopia compared to those with central or full-degree diplopia. Conclusions: The presence of diplopia was associated with the pre-operative LOM and EOM site but the type of diplopia was associated with LOM direction and EOM size. These factors can be used to predict the progression of diplopia in patients with isolated inferior orbital wall fracture.