Initial strabismus surgery in patients with thyroid eye disease: outcomes and dose-response in various types of procedure.

Purpose: Research on strabismus surgery for Thyroid Eye Disease (TED) is limited, with insufficient data on surgical dose-response. This study aimed to assess outcomes and dose-response in initial strabismus surgeries using a large TED sample.

Methods: A retrospective review of TED patients undergoing initial strabismus surgery (2013-2023) at Zhongshan Ophthalmic Center included data on demographics, ocular deviation, motility, surgical techniques, and outcomes. Surgeries involved rectus recession and tenotomy, with traction sutures (TS) applied for deviations > 35 prism diopters (PD). Success was defined as no diplopia and deviation ≤ 10 PD horizontally, ≤ 5 PD vertically. Dose-response (deviation change per mm rectus recession, DPR) and influencing factors were analyzed.

Results: Among 104 patients, rectus recession had a 70.65% success rate, while tenotomy achieved 12.5%. Success was highest for superior rectus (SR) recession (88.00%), followed by inferior rectus (IR) (70.00%) and medial rectus (MR) (38.46%). Two-muscle recessions succeeded in 55.56%. In single rectus recession with TS, DPR for IR, SR, and MR was 6.96 ± 2.18, 5.92 ± 1.14, and 9.78 ± 5.80 PD/mm, respectively, versus 4.26 ± 0.78, 3.95 ± 0.83, and 3.86 ± 0.29 PD/mm without TS. Preoperative deviation significantly affected DPR, especially in IR/SR surgeries (P < 0.001). Simultaneous MR recession did not alter IR/SR DPR in TS (P = 0.266) or non-TS (P = 0.138) groups. However, in non-TS cases, IR/SR recession impacted MR DPR (P = 0.034), but this effect was absent with TS (P = 0.741).

Conclusions: Single rectus recession achieves high success for TED vertical strabismus, with TS enhancing correction. Preoperative deviation is key to dose-response, while vertical recession influences horizontal dose-response when deviation is < 35PD.