Comparison of surgical outcomes between iStent and iStent inject W with ≥2 years of follow-up: a propensity score matching analysis.

PURPOSE: To compare real-world outcomes between first-generation iStent (G1) and iStent inject W (G2) combined with cataract surgery.

STUDY

DESIGN

Retrospective, propensity score-matched clinical investigation.

METHODS

Consecutive eyes treated with phaco-iStent (G1) or phaco-iStent inject W (G2) were matched 1:1 (n=115 per group) for age, preoperative intraocular pressure (IOP), medication score, axial length, and glaucoma subtype. Longitudinal changes in IOP and medication score were analyzed using linear mixed models. Surgical success was evaluated by Kaplan-Meier analysis under three prespecified criteria (A/B/C), and Cox models were used to estimate hazard ratios (HRs). Corneal endothelial cell density (ECD) and perioperative complications were recorded.

RESULTS

The baseline characteristics were balanced after matching. IOP decreased significantly from baseline at all visits in both groups except G1 at 24 months; the time-averaged IOP during follow-up was lower in G2 than in G1 (Δ=0.46 mmHg; p=0.018). The medication scores decreased postoperatively in both groups. Kaplan-Meier survival did not differ between devices (log-rank p=0.59, 0.996, and 0.509 for criteria A, B, and C, respectively). Lower preoperative IOP was consistently associated with higher failure risk according to Cox models. The generation effect was not significant, although a nonsignificant trend toward greater G2 benefit at lower IOP was observed under criterion A. The perioperative complication rates were similar.

CONCLUSION

Both devices provided moderate reductions in IOP and medication burden with favorable safety. G2 achieved a statistically significant but small reduction in mean IOP over time, while the time-to-failure outcomes were comparable. Baseline IOP strongly influences success, underscoring the importance of patient selection.