Intraocular pressure changes at different gaze positions after superior rectus muscle-lateral rectus muscle loop myopexy in highly myopic strabismus

Purpose To evaluate changes in intraocular pressure (IOP) at different gaze positions before and after superior rectus muscle-lateral rectus muscle (SR-LR) loop myopexy in highly myopic strabismus (HMS). Study design Nonrandomized clinical, prospective, interventional trial. Methods Fourteen patients with HMS (18 eyes) who underwent SR-LR loop myopexy were divided into 3 groups: 100 PD (large ET group), and > 100 PD, and simultaneous recession of the medial rectus (MR) muscle was performed (large ET + MR group). Intraocular pressure was measured preoperatively and postoperatively at the primary, abduction, and adduction positions in each group. Results Intraocular pressure did not change after surgery in the mild ET group. Intraocular pressure significantly decreased in the abduction position (from 20.0 ± 2.1 to 16.0 ± 1.9 mmHg, P = 0.043) in the large ET group and in the abduction (from 22.2 ± 5.9 to 15.6 ± 4.3 mmHg, P = 0.048) and primary positions (from 15.8 ± 5.0 to 10.2 ± 2.8 mmHg, P = 0.043) in the large ET + MR group. The preoperative significant differences in IOP between the abduction and adduction positions in the large ET group (7.4 ± 3.4 mmHg) and the large ET + MR group (10.0 ± 5.5 mmHg) disappeared postoperatively (3.2 ± 2.8 mmHg and 3.6 ± 1.7 mmHg, respectively). The differences in IOP between abduction and adduction were similar in all the groups. Conclusion SR-LR loop myopexy decreased IOP in patients with HMS in the abduction and primary positions.