Supplementary Material for: Indications and outcomes of posterior scleral contraction and pars plana vitrectomy in myopic traction maculopathy: a retrospective study

Purpose: This study aimed to characterize the differential indications and compare anatomical and visual outcomes between pars plana vitrectomy (PPV) and posterior scleral contraction (PSC) in eyes with myopic traction maculopathy (MTM). Methods: One hundred seventy-five eyes with MTM from 157 patients who were treated with PSC or PPV and had at least 6 months of follow-up were retrospectively analysed. Best-corrected visual acuity (BCVA) was used to assess visual outcomes. Anatomical outcomes were assessed using optical coherence tomography. Results: The PPV and PSC groups included 87 and 88 eyes, respectively. Eyes in the PPV group presented with higher presence of epiretinal membrane (93.1% vs. 69.3%, P<0.001), larger macular hole (MH) diameter (128.0 μm vs. 0 μm, P=0.01), and more severe pattern of MH (e.g., full thickness MH 18.4% vs. 10.2%, P<0.001), whereas achieved better anatomical outcomes (MH recovery rate: 89.9% vs. 50.0%, P <0.001; incidence of complete or essential recovery: 82.8% vs. 61.4%, P <0.001; the median time to recovery: 90 days vs. 307 days. P<0.001). Additionally, better recovery of retinal profile in PPV group tended to be more significant in eyes with axial length (AL) ≤30 mm. Conversely, eyes in the PSC group presented with more advanced MTM Staging System (e.g., stage 4 13.6% vs. 4.6%, P=0.003) and larger highest cavity of maculoschisis or macular detachment (389.3 ± 229.8 μm vs. 322.2 ± 216.4 μm, P=0.048), resulting in significant reduction in AL postoperatively (29.9 ± 1.6 mm before surgery vs. 28.2 ± 1.6 mm at last follow-up, P <0.001). In multivariate linear regression analysis, type of operation did not have a significant impact on BCVA at last follow-up or on change in BCVA after surgery. Conclusions: PPV was typically performed for eyes with severer vitreoretinal interface abnormalities and achieved better outcomes, particularly in eyes with AL ≤ 30mm. PSC was performed for eyes with advanced MTM Staging System, providing better axial stabilization despite slower anatomical improvement. Both approaches improved visual acuity to a similar extent, irrespective of the surgical technique employed.