Does vertical incomitance predict the diplopia outcome in orbital fracture patients? A prospective study of 188 patients

Objective: To determine the predictive value of vertical incomitance for diplopia outcome in orbital fracture patients. Patients and methods: A prospective cohort study composed of patients with orbital fractures was designed. The predictor variable was vertical incomitance, and the primary outcome variable was diplopia. Incomitance was calculated in prism diopters (Delta) as the difference of the maximum absolute deviation between the upper and lower three gaze directions. Standard statistics for patient characteristics, the Fisher exact test for categorical variables and the Wilcoxon rank sum test for continuous variables were computed. Results: The sample was composed of 188 patients grouped as follows: non-operated (n = 124) and operated (n = 64). Fifty-one patients showed vertical incomitance of whom 10 (19.6%) had persistent diplopia at the 1-year follow-up. The mean incomitance was 9.6 Delta in the diplopia group versus 2 Delta in the non diplopia group (OR = 1.13; p < 0.001). There was a statistically significant association between vertical incomitance of > 2 Delta and persistent diplopia at 1 year after adjusting for the surgery variable (OR = 1.07; p < 0.04). Conclusion: The present study has demonstrated that in orbital fracture patients, vertical incomitance was associated with (1) persistence of long-term diplopia, (2) the decision to perform surgery, and (3) the severity of the fracture. (C) 2018 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.