Slanted recession on bilateral lateral rectus for the treatment of intermittent Exotropia with convergence insufficiency

PURPOSE: To evaluate the efficacy and safety of slanted bilateral lateral rectus recession (S-BLRc) for the treatment of convergence insufficiency-type intermittent exotropia (CI-IXT) in children and to probe the relationship of the slanted amount and surgical outcomes. METHODS: Retrospective study. Fifty-eight patients with CI-IXT, aged 4 to 10 years old, underwent S-BLRc procedures. According to the different slanted amount between the upper and lower poles of lateral rectus, all the patients were grouped: Group A (slanting 1 mm, n = 22), Group B (slanting 1.5 mm, n = 18) and Group C (slanting 2 mm, n = 18). The successful surgical outcome was defined as deviation in the primary position ranging from exotropia< 8(△) to esotropia< 5(△) both at near and at distant as well as the near-distance difference (NDD) < 5(△). We analyzed and compared the preoperative and postoperative data including deviations both at near and at distance, NDD, objective torsion, horizontal deviation at up and down gaze, lateral incomitance, binocular vision and surgical success rate among three groups. RESULTS: The average deviations were significantly decreased from − 37.1(△) ± 4.2(△) (−,exotropia) to − 1.4(△) ± 4.6(△) at near (P < 0.05) and from − 25.8(△) ± 3.7(△) to − 0.1 ± 4.1(△) at distance (P < 0.05). The postoperative NDD on average was significantly reduced from 10.0(△) to 1.8(△) in Group A (P < 0.05), from 11.2(△) to 0.8(△) in Group B (P < 0.05) and from 13.3(△) to 0.9(△) in Group C (P < 0.05). There was a significant difference in the mean corrections of NDD among the three groups (8.2(△) in group A, 10.3(△) in group B and 12.4(△) in group C respectively, P < 0,05). All the patients attained various improvement of stereopsis after surgery. None had torsional diplopia, A-V pattern and lateral incomitance after strabismic surgery. Totally, the surgical success rate was 89.7% in our series at the 6- to 8-month follow-up. CONCLUSIONS: Slanted bilateral lateral rectus recession is an effective and safe procedure for the treatment of CI-IXT in children. S-BLRc can successfully collapse exotropia both at distance and at near, decrease NDD and benefit to gain binocular vision. The correction of NDD was associated with the slanted amount.