Long-term results of deeper muscle fibers recession of an inferior rectus operation.

PURPOSE: To report the efficacy in preventing lower eyelid retraction and long-term results of a new technique of inferior rectus (IR) recession for vertical strabismus and compare this method with the results obtained by a conventional IR recession operation.

METHODS

This retrospective study included 35 patients who underwent a new IR recession method (study group) and 22 patients who underwent the conventional IR recession (control group) for vertical strabismus. In the study group, an IR recession was applied to the deeper fibers and included approximately 90% of the IR muscle thickness. This group was divided into two subgroups: small IR recessions (4 to 6 mm) and large IR recessions (7 to 8 mm). In the control group, an IR recession of the entire muscle was applied without exceeding 6 mm. The photographs were analyzed for lower eyelid position. Digital image analysis was used to standardize each patient's preoperative and postoperative photographs at final follow-up examination. The main outcome measures were the margin-to-reflex distance, lower eyelid retraction, and vertical deviation angles (at near and distance fixation).

RESULTS

The mean change in margin-to-reflex distance after surgery was 0.03 mm in the small IR recessions group, 0.1 mm in the large IR recessions group, and 2.04 mm in the control group. Postoperatively, the lower eyelid retraction in the study group, which occurred after both small and large IR recessions, was significantly less than that in the control group (P < .001). There was no significant difference between the study and control groups in improvements in near and distance vertical deviations and success ratios (P > .05).

CONCLUSIONS

At long-term follow-up, recession of the deeper fibers layer, including approximately 90% of the IR muscle thickness, was a procedure that minimized or eliminated the possibility of lower eyelid retraction and did not limit the success of strabismus surgery.