Long-term comparative outcomes of Hydrus versus iStent inject microinvasive glaucoma surgery implants combined with cataract surgery.

Aim: To compare the long-term effectiveness of combined phacoemulsification and Hydrus microstent (phaco-Hydrus) versus iStent inject (phaco-iStent) using microinvasive glaucoma surgery-specific surgical success definitions in a large observational cohort.

Methods: Retrospective study of eyes in the Fight Glaucoma Blindness registry that underwent phaco-Hydrus or phaco-iStent with a minimum of 48 months follow-up. The prespecified primary endpoint was ≥20% intraocular pressure (IOP) decrease and IOP ≤21 mm Hg or ≥1 medication reduction versus baseline at 48 months with no preoperative washout. Propensity score matching of baseline covariates was used to examine outcomes in a subcohort (matched cohort).

Results: 431 eyes (98 phaco-Hydrus: 331 phaco-iStent) were included in the overall cohort and 177 eyes (59 phaco-Hydrus: 118 phaco-iStent) in the matched cohort. There was no significant difference in the rate of surgical success between each group in achieving the primary endpoint at 48 months (adjusted overall cohort, 41.2% vs 43.0% in phaco-Hydrus vs phaco-iStent respectively, p=0.81; matched cohort, 44.1% vs 43.2%, p=0.99). There was no significant difference in degree of IOP reduction, medication reduction and adjusted secondary outcomes between the phaco-Hydrus and phaco-iStent groups in both overall and matched cohorts. The incidence of adverse events and secondary procedures was similar between both groups.

Conclusion: There was no significant difference in surgical success between phaco-Hydrus and phaco-iStent groups at 48 months. Over 40% of eyes maintained the primary success endpoint of ≥20% IOP decrease and IOP ≤21 mm Hg or ≥1 medication reduction versus baseline without the need for secondary glaucoma surgery.