Three-Year Outcomes of iStent Inject W Implantation Combined With Phacoemulsification in Japanese Eyes With Open-Angle Glaucoma: A Retrospective Study

Background Glaucoma is a leading cause of irreversible blindness. In Japan, most primary open-angle glaucoma (POAG) cases are normal-tension glaucoma (NTG). Micro-invasive glaucoma surgery (MIGS) such as the iStent inject W (Glaukos Corporation, San Clemente, CA) offers a less invasive option, but long-term outcomes in NTG-predominant populations are scarce. Objective The objective of this study is to evaluate three-year outcomes of combined phacoemulsification and iStent inject W implantation in Japanese eyes with POAG. Methods This retrospective study included 24 eyes from 14 Japanese patients undergoing combined surgery between February 2021 and May 2022 at Chutoen General Medical Center. Eyes with prior glaucoma surgery (except laser trabeculoplasty) or secondary glaucoma were excluded. Intraocular pressure (IOP) and medication scores were recorded up to 36 months postoperatively. Changes from baseline were analyzed with the Wilcoxon signed-rank test. Results Mean IOP decreased from 16.71 ± 4.54 mmHg to 12.63 ± 2.59 mmHg at 36 months (p < 0.001), 24% reduction. Medication scores decreased from 3.17 ± 1.55 to 1.42 ± 1.10 (p < 0.001). At 36 months, out of 24 eyes, eight eyes (33.3%) were medication-free, and 14 eyes (58.3%) achieved ≥20% IOP reduction. No additional glaucoma surgeries were required. Complications were minimal, with transient hyphema in two eyes (8.3%) and transient IOP elevation at one week in two eyes (8.3%). Conclusion iStent inject W combined with phacoemulsification provided safe and sustained IOP and medication reduction over three years in Japanese eyes with POAG, supporting its use in NTG-predominant populations.