8 for the iStent inject Study Group* Purpose: Evaluate the safety and effectiveness of an ab interno implanted (iStent inject) Trabecular Micro-Bypass System (Glaukos Corporation, San Clemente, CA) in combination with cataract surgery in subjects with mild to moderate primary open-angle glaucoma (POAG). Design: Prospective, randomized, single-masked, concurrently controlled, multicenter clinical trial. Participants: Eyes with mild to moderate POAG and preoperative intraocular pressure (IOP) 24 mmHg on 1 to 3 medications, unmedicated diurnal IOP (DIOP) 21 to 36 mmHg, and cataract requiring surgery. Methods: After uncomplicated cataract surgery, eyes were randomized 3:1 intraoperatively to ab interno implantation of iStent inject (Model G2-M-IS; treatment group, n ¼ 387) or no stent implantation (control group, n ¼ 118). Subjects were followed through 2 years postoperatively. Annual washout of ocular hypotensive medication was performed. Main Outcome Measures: Effectiveness end points were !20% reduction from baseline in month 24 unmedicated DIOP and change in unmedicated month 24 DIOP from baseline. Safety measures included best spectacle-corrected visual acuity (BSCVA), slit-lamp and fundus examinations, gonioscopy, pachymetry, specular microscopy, visual fields, complications, and adverse events. Results: The groups were well balanced preoperatively, including medicated IOP (17.5 mmHg in both groups) and unmedicated DIOP (24.8AE3.3 mmHg vs. 24.5AE3.1 mmHg in the treatment and control groups, respectively, P ¼ 0.33). At 24 months, 75.8% of treatment eyes versus 61.9% of control eyes experienced !20% reduction from baseline in unmedicated DIOP (P ¼ 0.005), and mean reduction in unmedicated DIOP from baseline was greater in treatment eyes (7.0AE4.0 mmHg) than in control eyes (5.4AE3.7 mmHg; P < 0.001). Of the responders, 84% of treatment eyes and 67% of control eyes were not receiving ocular hypotensive medication at 23 months. Furthermore, 63.2% of treatment eyes versus 50.0% of control eyes had month 24 medication-free DIOP 18 mmHg (difference 13.2%; 95% confidence interval, 2.9e23.4). The overall safety profile of the treatment group was favorable and similar to that in the control group throughout the 2-year follow-up. Conclusions: Clinically and statistically greater reductions in IOP without medication were achieved after iStent inject implantation with cataract surgery versus cataract surgery alone, with excellent safety through 2 years.

Bovine Kir7.1 clones were obtained from a retinal pigment epithelium (RPE)‐subtracted cDNA library. Human RPE cDNA library screening resulted in clones encoding full‐length human Kir7.1. Northern blot analysis indicated that bovine Kir7.1 is highly expressed in the RPE. Human Kir7.1 channels were expressed in Xenopus oocytes and studied using the two‐electrode voltage‐clamp technique. The macroscopic Kir7.1 conductance exhibited mild inward rectification and an inverse dependence on extracellular K+ concentration ([K+]o). The selectivity sequence based on permeability ratios was K+ (1.0) ≈ Rb+ (0.89) > Cs+ (0.013) > Na+ (0.003) ≈ Li+ (0.001) and the sequence based on conductance ratios was Rb+ (9.5) >> K+ (1.0) > Na+ (0.458) > Cs+ (0.331) > Li+ (0.139). Non‐stationary noise analysis of Rb+ currents in cell‐attached patches yielded a unitary conductance for Kir7.1 of ≈2 pS. In whole‐cell recordings from freshly isolated bovine RPE cells, the predominant current was a mild inwardly rectifying K+ current that exhibited an inverse dependence of conductance on [K+]o. The selectivity sequence based on permeability ratios was K+ (1.0) ≈ Rb+ (0.89) > Cs+ (0.021) > Na+ (0.003) ≈ Li+ (0.002) and the sequence based on conductance ratios was Rb+ (8.9) >> K+ (1.0) > Na+ (0.59) > Cs+ (0.23) > Li+ (0.08). In cell‐attached recordings with Rb+ in the pipette, inwardly rectifying currents were observed in nine of 12 patches of RPE apical membrane but in only one of 13 basolateral membrane patches. Non‐stationary noise analysis of Rb+ currents in cell‐attached apical membrane patches yielded a unitary conductance for RPE Kir of ≈2 pS. On the basis of this molecular and electrophysiological evidence, we conclude that Kir7.1 channel subunits comprise the K+ conductance of the RPE apical membrane.