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  • Schlemm Canal Microstent in Patients With POAG and Cataract

    By Lynda Seminara
    Selected By: Stephen D. McLeod, MD
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    Journal Highlights

    Ophthalmology, January 2019

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    Samuelson et al. compared the safety and effectiveness of cataract surgery alone versus the Hydrus microstent (Ivantis) in conjunction with cataract surgery. They found that the combination was more effective at lowering intra­ocular pressure (IOP) by month 12 and month 24. Safety findings for the study groups were similar.

    Enrollees of this single- masked trial had concomi­tant primary open-angle glaucoma (POAG), visually significant cataract, and washed-out modified diurnal IOP (MDIOP) ranging from 22 mm Hg to 34 mm Hg. After uncomplicated phacoemulsification, patients were assigned randomly (2:1) to receive either a single Hydrus microstent in the Schlemm canal or no stent. Compre­hensive eye exams were performed at eight postoperative points, from the first day following surgery to month 24. Medication washout and MDIOP measurements were repeated at 12 and 24 months. The primary measure of effectiveness was the proportion of sub­jects with a reduction of at least 20% in unmedicated MDIOP. The second­ary measure was the change in mean MDIOP from baseline.

    Use of topical medication for hypotension was tracked throughout follow-up. Safety measures included the frequency of surgical complications and the occurrence of adverse events.

    After phacoemulsification, 369 eyes received the microstent and 187 did not. By month 24, unmedicated MDIOP had declined by ≥20% in 77.3% of the stent-treated group and in 57.8% of the control group. The mean reduction in unmedicated MDIOP from baseline to 24 months was –7.6 mm Hg in the stent-treated group and –5.3 mm Hg in the control group. The mean number of medications declined from 1.7 at baseline to 0.3 by 24 months in the stent group and from 1.7 to 0.7 in the control group. (All p values < .001.) No serious ocular adverse events were associated with the microstent. Overall, safety findings were similar for the study groups. The microstent group had a higher rate of focal adhesions, and the control group had more IOP-related complications.

    The authors recommend that long-term head-to-head studies be performed to better understand the ef­ficacy and safety of microstent implan­tation and to compare this adjunct with other novel minimally invasive devices.

    The original article can be found here.