Modified Target Angle as a Predictor of Success in Strabismus Management after Orbital Fracture

Abstract

Surgery for strabismus secondary to orbital fracture reconstruction surgery has had low success rates and high reoperation rates due to its incomitant nature and complex underlying mechanisms. There has been no consensus as to which of the various methods for improving the surgical results are best. We proposed a modified target angle criteria that combined the regular target angle and a favorable Hess area ratio percentage (HAR%) threshold to evaluate surgical results within the first postoperative week and conducted a retrospective chart review. According to the criteria of the modified target angle at the first postoperative week, a total of 63 patients were divided into two groups: Group 1, patients who fulfilled the criteria (49 patients); and Group 2, those who did not (14 patients). Sex, type of fracture, and the use of porous polyethylene sheets and titanium mesh during reconstruction surgery were significantly different between the groups. Group 1 showed a significantly higher percentage of patients who met the criteria of HAR% > 65% at the first week and >85% (i.e., a successful outcome) at the 6-month visit (p < 0.01). Additionally, Group 1 had a higher HAR% at the first postoperative week (p < 0.01). In conclusion, the patients meeting the criteria of the modified target angle at the first postoperative week had a favorable outcome at the 6-month visit in both ocular alignment and ocular movement.