Outcomes of the 63-μm Gelatin Microstent Versus 45-μm Gelatin Microstent: An International Multicenter Study

To compare 12-month effectiveness and safety of 63-μm gelatin microstent (Xen63) versus 45-μm gelatin microstent (Xen45).

Multicenter, retrospective cohort study.

Two hundred eyes of 200 patients (100 in each Xen63 and Xen45 group), with or without phacoemulsification.

Consecutive patients undergoing 63-μm microstent implantation across 4 countries (Canada, Italy, Austria, and Belgium) were compared with matched controls who underwent 45-μm microstent implantation.

Primary outcome measure was the probability of complete success at 1 year: (1) no 2 consecutive intraocular pressure (IOP) >14 or < 6 mmHg with 2 lines of vision loss and (2) ≥20% reduction from decision IOP, without glaucoma medications or reoperations. Qualified success allowed glaucoma medications and laser trabeculoplasty. Secondary outcomes included success with upper IOP cutoffs of 17 and 21 mmHg, postoperative IOP and medications course, complications, interventions, and reoperations.

Complete success favored 63-μm microstent (56.9% vs. 43.9%, P = 0.017), using IOP cutoff of 14 mmHg. The 45-μm microstent was associated with an increased hazard of failure compared with the 63-μm microstent (hazard ratio, 1.9; 95% confidence interval, 1.2-3.0). Complete success using IOP cutoffs of 17 and 21 mmHg in the 63- versus 45-μm group was 60.1% versus 53.9% (P = 0.156) and 60.1% versus 55.0% (P = 0.243), respectively. Qualified success was not significantly different between the 2 groups using any IOP threshold (P > 0.05). At 12 months, the 63-μm group had significantly lower IOP (mean, 14.6 ± 7.6 vs. 15.8 ± 6.1 mmHg; P = 0.021) and medication count (0.6 ± 1.1 vs. 1.1 ± 1.5; P = 0.024). Postoperative needling was performed in 16.0% and 18.0% of 63- and 45-μm microstent-implanted eyes, respectively. Incidence of early postoperative choroidal effusion was higher in the 63-μm group (25.0% vs. 6.0%; P < 0.001). Interventions (62.0% vs. 59.0%) and reoperations (21.0% vs. 15.0%) were comparable between the groups (P > 0.050).

Xen63 demonstrated superior IOP-lowering effectiveness compared with its 45-μm variant in patients requiring more robust IOP targets. Xen63-implanted eyes experienced a higher incidence of early postoperative choroidal effusion, the majority of which were transient.

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