Unilateral versus bilateral lateral rectus recession for correction of small to moderate angle exotropia

To compare the effect of unilateral versus bilateral lateral rectus (LR) recession for correction of small to moderate exotropia.

Records of all patients with exotropia 14–35 prism diopters (∆), operated upon by the authors, were included in a retrospective study to compare the effect of unilateral (Group 1) versus bilateral (Group 2) LR recession. The study end-point was the last follow-up visit scheduled at least 3 months postoperatively. A successful outcome was defined as 0–10∆ of horizontal tropia.

The study included 154 patients (47 in Group 1 and 107 in Group 2). Patients were followed up for 3–120 months (26.7 ± 24.88). A successful outcome was achieved in 83% in Group 1 and 82.2% in Group 2 (p = .976), with higher success in group 1 for surgical target angles up to 25∆. All failures in Group 1 were due to undercorrections., while the 17.8% failure rate in Group 2 comprised 15% undercorrections and 2.8% overcorrections (p = .419). Persistent lateral incomitance was seen in 29.5% in Group 1 versus 2.3% in Groups 2 (p < .001). Lateral incomitance was encountered in 71% of those undergoing 10 mm unilateral recessions, versus 20% of those who had smaller recession doses. Limited ductions were mild, and exceeded -1 in only 4 cases: 3 had had 10 mm and 1 had had 9 mm unilateral LR recession.

Unilateral and bilateral LR recessions offer essentially equal success rates. Unilateral recessions are advised for angles up to 25∆, without exceeding 10 mm.