To compare the surgical outcomes between modified bilateral lateral rectus muscle (BLR) recession and augmented unilateral recession-resection (R&R) for the convergence insufficiency intermittent exotropia (IXT).

37 patients with convergence insufficiency IXT were divided into two groups: 13 patients (underwent BLR recession) and 24 patients (underwent unilateral R&R). Success was defined as within 10 prism diopters (PD) at distance and near, and within 10 PD of the difference between them at postoperative 12 months.

After the patch test, the preoperative distance deviation angle in the BLR group was 29.9 ± 8.4 PD, and the near deviation angle was 42.3 ± 9.7 PD; the difference between them was 12.5 ± 3.2 PD. In the R&R group, the preoperative distance deviation angle was 26.7 ± 5.8 PD, and the near deviation angle was 41.5 ± 7.4 PD; the difference between them was 14.8 ± 4.3 PD ( p = 0.235, p = 0.987, and p = 0.123). At the 12-month follow-up in the BLR group, the distance angle was 3.8 ± 5.1 PD, and the near deviation angle was 4.9 ± 6.1 PD; the difference between them was 2.9 ± 5.9 PD. In the R&R group, the postoperative distance deviation angle was 4.7 ± 6.1 PD, and the near deviation angle was 7.9 ± 6.6 PD; the difference between them was 3.65 ± 5.1 PD ( p = 0.708, p = 0.162, and p = 0.632, respectively). The surgical success rate did not differ significantly between groups at 12 months postoperatively (76.9%: BLR group and 70.8%: R&R group; p = 0.690).

Modified BLR recession showed a similar surgical success rate to augmented unilateral R&R, and was effective in reducing both distance and near exodeviation, and in decreasing the difference between distance and near deviation in convergence insufficiency IXT.