Three-Year Outcomes of a Schlemm Canal Microstent (Hydrus Microstent) with Concomitant Phacoemulsification in Open-Angle Glaucoma

Abstract

Purpose: HORIZON trials have reported the medium- and long-term outcomes of the Hydrus microstent. However, outside of randomized clinical trials, outcomes beyond 24 months have not been previously reported. Here, we examine the 3-year outcomes of the Hydrus microstent with cataract surgery outside of a randomized clinical trial setting.

Design: Single-surgeon consecutive case series.

Participants: Glaucomatous eyes that underwent implantation of a Hydrus microstent with concomitant cataract surgery at a single ophthalmology center in Montreal, Canada.

Methods: Success was defined according to the absence of specific failure criteria: (A) glaucoma reoperation; (B) selective laser trabeculoplasty; (C) intraocular pressure (IOP) < 5 mmHg, > 18 mmHg, or increase in the number of antiglaucoma medications (AGMs) used (after the first postoperative month), or loss of light perception due to glaucoma; (D) aggregation of criteria A-C. Predictors of treatment failure and postoperative changes in IOP and AGM use were assessed. Safety included best-corrected visual acuity (BCVA), cup-to-disc ratio (CDR), retinal nerve fiber layer (RNFL) thickness, ganglion cell inner plexiform layer (GC-IPL) thickness, visual field mean deviation (VF-MD) and pattern standard deviation (VF-PSD), and adverse events.

Main outcome measures: Surgical success, predictors of treatment failure, postoperative changes in IOP and AGM use, and structural and functional markers of disease stability.

Results: One hundred six eyes were included. The 3-year surgical success according to Criteria A to D was 86%, 83%, 91%, and 67%, respectively. Intraocular pressure decreased by 26.5% from 18.9 ± 4.8 to 13.9 ± 2.3 mmHg (P < 0.001) and AGM use reduced by 33% from 3.0 ± 1.2 to 2.0 ± 1.2 medications (P < 0.001). The postoperative improvement in BCVA was preserved (P < 0.001). The structural and functional markers of disease stability, including CDR, RNFL, and GC-IPL thickness, as well as VF-MD and VF-PSD, remained stable (P > 0.05). Postoperative adverse events were few and transient.

Conclusions: The 36-month results from this study show that the Hydrus microstent with phacoemulsification is safe and effective in reducing the IOP and AGM among patients with mild to severe open-angle glaucoma and can slow down the disease progression by preserving both structural and functional parameters.

Financial disclosure(s): Proprietary or commercial disclosure may be found after the references.

Keywords: Combined glaucoma surgery; Hydrus microstent; Minimally invasive glaucoma surgery (MIGS); Schlemm canal microstent; Schlemm canal scaffold.