JUL 01, 2022
Enduring Effects of Microstent Use
By Lynda Seminara
Selected by Russell N. Van Gelder, MD, PhD
Glaucoma
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.