Background: Early postoperative hypotony remains a significant complication following PreserFlo MicroShunt (PMS) implantation, potentially leading to serious sequelae including choroidal detachment and hypotensive maculopathy. This study evaluated the effectiveness of intraoperative 9– 0 nylon thread insertion (NTI) technique in preventing hypotony-related complications. Methods: This retrospective comparative study included 81 eyes of 63 patients who underwent PMS implantation with mitomycin C between September 2023 and June 2025. Eyes were divided into NTI group (59 eyes, 42 patients) and Non-NTI group (22 eyes, 21 patients). The primary outcome was the incidence of composite hypotony-related complications (choroidal detachment and/or hypotensive maculopathy) during 6-month follow-up. Secondary outcomes included intraocular pressure (IOP) changes, medication score reduction, and timing of suture removal. Statistical analyses incorporated cluster correction for bilateral cases. Results: Baseline characteristics, including glaucoma subtype distribution, were comparable between groups. The composite hypotony-related complication rate was significantly lower in the NTI group (11.9% vs 54.5%, p< 0.001; odds ratio 0.112, 95% CI 0.039– 0.321). Kaplan-Meier analysis demonstrated superior complication-free survival in the NTI group (log-rank p< 0.001, hazard ratio 0.094, 95% CI 0.035– 0.252). The median IOP at postoperative day 1 was significantly higher in the NTI group (10.0 8.0– 14.0 vs 5.8 5.0– 8.5 mmHg, p< 0.001), indicating effective early hypotony prevention. At 6 months, both groups achieved comparable IOP control (13.0 10.9– 14.0 vs 13.0 11.0– 16.0 mmHg, p=0.324) with medication-free rates of 74.6% and 59.1%, respectively (p=0.190). Conclusion: Intraoperative 9– 0 nylon thread insertion significantly reduces hypotony-related complications following PMS implantation without compromising IOP control at 6 months or medication reduction, representing a safe and effective surgical modification. Keywords: PreserFlo MicroShunt, glaucoma surgery, hypotony prevention, nylon thread insertion, choroidal detachment, hypotensive maculopathy
Matsuoka et al. (2026) studied this question.