Early and late postoperative alignment following unilateral lateral rectus recession for intermittent exotropia

Bilateral lateral rectus recession is useful in the treatment of intermittent exotropia. A unilateral recession may be used in the treatment of small-to-moderate angle intermittent exotropia as well. An early overcorrection following bilateral surgery has been shown to carry the best prognosis for future alignment. The relationship between the early and late postoperative alignment following unilateral surgery is unknown. The current study was designed to establish this relationship.

Thirty-seven patients undergoing a unilateral lateral rectus recession for intermittent exotropia were prospectively evaluated to determine the relationship between early and late postoperative alignment. Patients were evaluated 1 week and 6 months following surgery. A satisfactory result was considered to be alignment within 8 prism diopters (delta).

Of the 37 patients who underwent surgery, 35 completed the study. Overall, 77% of patients achieved a satisfactory result at the 6-month exam (27/35). Satisfactory alignment at 6 months was obtained in all patients who were orthophoric (14/14), 77% (10/13) of patients with an exodeviation less than 9 delta (10/13), and 60% (3/5) of patients with an exodeviation less than 9 delta at the 1-week postoperative exam. Twenty-nine percent of patients changed alignment status during this time period (10/35), and 29% of all patients became more divergent (10/35). The average divergent shift for the entire group was 1.6 delta and was not significant. Among those patients who experienced a divergent shift, the average amount was 6 delta.

There is not a significant difference in early versus late alignment following unilateral lateral rectus recession. Surgeons performing this procedure should not expect a significant divergent shift from the first postoperative week. Unlike bilateral recessions where an early overcorrection is desirable, acceptable alignment in the first week following surgery carries the best prognosis for later alignment.