Postoperative change in lateral rectus muscle insertion measured by anterior segment optical coherence tomography

AimsThe aims of this study were to investigate the longitudinal change in lateral rectus (LR) muscle insertion after recession surgery, and to evaluate a relationship between insertion distance and postoperative amount of deviation.MethodsWe recruited 31 patients who underwent primary LR recession surgery with normal anterior segment structures. An AS-OCT scan of the LR muscle was performed at every visit. Data on sex, age, degree of deviation (prism diopter), and spur-LR insertion distance using AS-OCT were collected at preoperatively and postoperative months 1, 3, and 6. Spur-LR insertion was defined as the shortest distance between the insertion of the LR muscle and the scleral spur was measured using the caliper function in the AS-OCT software.ResultsThe mean distance of spur-LR insertion measured with AS-OCT was 5.5±0.7 mm preoperatively, and 11.1±0.9 mm at 1 month, 11.5±0.8 mm at 3 months, and 11.0±0.7 mm at 6 months postoperatively. There were significant differences in spur-LR insertion between postoperative 1 and 3 months, and between 3 and 6 months (generalized estimating equation, all P<0.001). The overall spur-LR insertion measurement has a significantly negative correlation with postoperative amount of deviation (Pearson's correlation, P=0.035, r=-0.218).ConclusionsAS-OCT is a useful instrument for understanding postoperative changes in EOM after tissue swelling subsides.