Preoperative factors associated with multiple strabismus surgeries in basic exotropia

To compare the preoperative clinical features in patients with basic unilateral exotropia who underwent single versus two and three or more strabismus surgeries.

retrospective.

Two thousand four hundred fifty-seven patients with unilateral basic exotropia were recruited over 10 years. Of these, 1886 (76.8%) had one surgery, 411 (16.7%) had two, and 160 (6.5%) had three or more surgical interventions. Preoperative data included the best corrected distance visual acuity (BCVA), refractive error, magnitude of exotropia, and amblyopia type and severity.

The mean age at first surgery was 26.3 ± 13.35 years (age range: 2-77) with no significant difference between groups with one, two, and three or more surgeries (p = 0.770). Mean BCVA in the strabismic eye was significantly worse in patients who underwent three or more surgeries (0.82 ± 0.076 logMAR) than those who had one (0.55 ± 0.018 logMAR; p < 0.001) or two surgeries (0.52 ± 0.038 logMAR; p < 0.001). Spherical equivalent refraction in the strabismic eye was significantly more hyperopic in patients who underwent three or more surgeries (0.79 ± 0.37 D), compared with those with one (-0.95 ± 0.094 D; p < 0.001) or two surgeries (-0.36 ± 0.16 D; p < 0.001). Relative to one surgery, undergoing two surgeries was independently associated with larger distance horizontal deviation (adjusted odds ratio (aOR) per prism diopter = 1.012; 95% CI, 1.003-1.022; p = 0.009). Undergoing three or more surgeries was independently associated with amblyopia severity (aOR = 2.368; 95% CI, 1.279-4.384; p = 0.006); in the strabismic eye, and higher spherical power markedly increased the odds (aOR = 13.553; 95% CI, 12.801-14.348; p < .001).

Worse preoperative BCVA, greater hyperopia, and higher angle of deviation were associated with a greater likelihood of requiring more than one surgery. Surgeons should optimize preoperative refractive and amblyopia management and counsel high-risk patients about the increased likelihood of additional procedures.