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  • The iStent inject for POAG: Safety and Efficacy Results

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

    Ophthalmology, June 2019

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    Microinvasive glaucoma surgery (MIGS) may offer sustained reduction of intra­ocular pressure (IOP) while avoiding the drawbacks of ocular hypotensive drugs and filtering surgery. The first FDA-approved MIGS device, the iStent (Glaukos), has been used successfully in patients with open-angle glaucoma undergoing concomitant cataract sur­gery. A newer device, the iStent inject Trabecular Micro-Bypass System (also by Glaukos), creates two patent bypass­es through the trabecular meshwork. Samuelson et al. looked at the safety and effectiveness of combining this approach with cataract surgery in pa­tients with mild or moderate primary open-angle glaucoma (POAG). Relative to cataract surgery alone, the system achieved greater IOP reductions, and the two-year safety profile was good.

    This multicenter study included 505 eyes with mild or moderate POAG that also required cataract surgery. Preoper­ative IOP was ≤24 mm Hg (with one to three medications), and unmedicated diurnal IOP ranged from 21 mm Hg to 36 mm Hg. After uncomplicated cata­ract surgery, eyes were randomized intraoperatively to receive either the iStent inject (treatment group, n = 387) or no stent (control group, n = 118). Follow-up lasted two years and includ­ed annual washout of ocular hypo­tensive medication. The effectiveness endpoints were ≥20% reduction from baseline to month 24 in unmedicated diurnal IOP and change in unmedicated diurnal IOP from baseline to month 24. Safety measures included gonioscopy, pachymetry, and slit-lamp and fundus examinations; visual field and acuity tests; and documentation of adverse events.

    The preoperative mean medicated IOP was 17.5 mm Hg in both groups; mean unmedicated diurnal IOP was 24.8 ± 3.3 mm Hg in the treatment group and 24.5 ± 3.1 mm Hg in con­trols. By 24 months, 75.8% of treated eyes and 61.9% of control eyes had a reduction from baseline in unmedicated diurnal IOP of at least 20% (p = .005). The mean reduction was greater in the treatment group (7.0 vs. 5.4 mm Hg; p < .001).

    Among responders, 84% of treated eyes and 67% of control eyes were not receiving ocular hypotensive agents at 23 months. By month 24, medication-free diurnal IOP ≤18 mm Hg was achieved in 63.2% of treated eyes and 50.0% of control eyes. The safety profiles were favorable and similar.

    The original article can be found here.