Clinical Outcomes of Trabecular Micro-Bypass Stent in Patients with Moderate to Severe Open-Angle Glaucoma

To evaluate 1-year clinical outcomes and response markers after implantation of a trabecular micro-bypass stent (iStent inject® W) in patients with moderate-to-severe open-angle glaucoma (OAG).

This retrospective cohort study included 22 eyes of 22 patients with moderate-to-severe OAG who underwent standalone iStent inject® W implantation (n = 4) or combined phacoemulsification with iStent inject® W (n = 18). Qualified surgical success was defined as intraocular pressure (IOP) ≤15 mmHg with glaucoma medications and either ≥25% IOP reduction or final IOP ≤12 mmHg if baseline IOP was ≤15 mmHg. Kaplan-Meier analysis was used for cumulative probability of success; Cox proportional hazards regression analysis was used to identify response markers of surgical failure.

Based on 19 eyes after censoring 3 eyes requiring additional surgery, IOP reduced from 22.09 ± 5.62 mmHg preoperatively to 12.37 ± 2.43 mmHg at 1 year (p < 0.001). Cumulative qualified success rates were 90.9% at 6 months and 72.7% at 12 months. No statistically significant changes were observed in the number of IOP-lowering medications. Higher postoperative IOP at 1 week and 1 month were independently associated with a higher surgical failure rate (1 week: hazard ratio [HR], 1.118; p = 0.007, 1 month: HR, 1.341; p = 0.031). Transient hyphema occurred in 7 eyes and resolved within 1 week; iStent iris plugging occurred in 2 eyes; and 3 eyes required subsequent trabeculectomy.

iStent inject® W appeared to provide meaningful IOP reduction and may serve as an intermediate option in patients with moderate-to-severe OAG. Early higher postoperative IOP may be an early response marker associated with surgical failure.