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  • Enduring Effects of Microstent Use

    By Lynda Seminara
    Selected by Russell N. Van Gelder, MD, PhD
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    Journal Highlights

    Ophthalmology, July 2022

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    Randomized trials of the Hydrus Micro-stent (HMS) have found that it signifi­cantly reduces IOP and medication burden through two years following surgery for primary open-angle glau­coma (POAG). By year 3, recipients of the HMS were less likely to require additional incision surgery for glauco­ma. Subsequently, Ahmed et al. looked at five-year outcomes of the HORIZON trial, in which cataract surgery alone was compared with combined cataract/glaucoma surgery with the HMS. They found that the stent group had greater reductions in IOP, lower medication use, and less need for post-op incisional glaucoma-filtration surgery. Long-term presence of the implant did not ad­versely affect corneal endothelial cells.

    HORIZON was a prospective, multicenter, randomized controlled trial. Participants included those with cataract and POAG who had received at least one glaucoma medication and had not undergone incisional surgery for glaucoma. Washed-out diurnal IOP ranged from 22 to 34 mm Hg. Eyes were assigned randomly (2:1) to receive either the HMS or no stent after suc­cessful cataract surgery. Main outcomes included IOP, use of glaucoma medica­tion postoperatively, need for addition­al glaucoma surgery, visual acuity and visual field, procedure-related adverse events, and endothelial cell counts.

    Of the original HORIZON cohort, five-year follow-up was complete for 83.5% of the HMS group and 71.7% of those who underwent cataract surgery alone. At five years, the HMS group had a higher proportion of eyes with IOP £18 mm Hg (49.5% vs. 33.8%; p = .003) and greater likelihood of an IOP reduction of at least 20% (54.2% vs. 32.8%; p < .001). The number of glaucoma medications used at the five-year mark was 0.5 ± 0.9 in the HMS group and 0.9 ± 0.9 in the cat­aract surgery–only group (p < .001); no glaucoma medication was used in 66% of HMS eyes and 46% of cataract surgery–only eyes (p < .001). Moreover, the cumulative risk of further incisional surgery was lower in the HMS group (2.4% vs. 6.2%; p = .027). From three to 60 months post-op, no clinically or statistically significant differences were noted in the rate of endothelial cell loss.

    The authors emphasized that by reducing medication burden and low­ering risk of repeat glaucoma surgery, the HMS would likely have durable and meaningful effects on quality of life. The results suggest that HMS place­ment at time of cataract surgery offers long-term benefit for management of POAG.

    The original article can be found here.