The influence of preoperative ocular misalignment on anatomic outcomes in patients undergoing surgical re-alignment for exotropia.

Abstract

Purpose : Various clinical and surgery related factors are reported to influence postoperative alignment in patients who are operated for exotropia (XT). The purpose of this study was to evaluate whether successful outcomes were dependent on the magnitude of preoperative misalignment in patients with XT.

Methods : Subjects with the diagnosis of XT were included in this retrospective study. Patients with sensory XT and those with vertical deviations were not included. Type of correction involved either unilateral recess-resect procedure (RNR) or bilateral rectus recession (BLR). Deviation measurements were obtained at baseline, 1-week, and 1-year postoperatively at distance (D) and near (N) fixation. Successful outcome was defined as a misalignment within ± 8 PD.

Results : Thirty-six patients (14M/22F) with a mean age of 14.1±14.6 years (range 2-59 years) were included in the study. For the RNR group, the D_preop was 33.6±9.1 PD and N_preop 33.3±13.9 PD. Postoperative 1-week and 1-year deviations were measured as D_1week: 1.3±4.3 PD, N_1week: 0.3±5.7 PD and D_1year: -3.9±7.3 PD, N_1year: -2.5±8.9 PD, respectively. In the RNR group, successful outcome was attained in 93% of cases for distance and 86% for near at 1-week and 71% of cases for distance and 79% of those for near at 1-year of follow-up. For the BLR group, the D_preop was 32.3±7.0PD and N_preop was 30.7±10.5 PD. Postoperative 1-week and 1-year deviations were measured as D_1week: 3.6±6.1 PD, N_1week: 2.5±7.1 PD and D_1year: -4.9±10.9 PD, N_1year: -3.3±14.6 PD, respectively. In the BLR group, successful outcome was attained in 86% of cases for distance and 77% for near at 1-week and 50% of cases for distance and 55% for near at 1-year of follow-up. There was no significant difference between rates of successful alignment between RNR and BLR procedures for distance (p=0.30) and near (p=0.17) deviations at 1-year of follow-up. There was also no significant difference in the preoperative magnitude of deviation in subjects who ended up with successful alignment versus those who had unsuccessful outcomes at the end of 1 year of follow-up (p=0.76 for distance and p=0.09 for near).

Conclusions : The preoperative magnitude of misalignment is not a factor determining the rate of successful outcomes in patients with XT who undergo either RNR or BLR type of surgical correction.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.