Clinical Outcomes After Second-Generation Trabecular Microbypass Stents (iStent inject®) with Phacoemulsification in Korean Patients

INTRODUCTION: To evaluate the intraocular pressure (IOP)-lowering effect of second-generation trabecular microbypass stents (iStent® inject) with cataract extraction (combination group) and compare refractive changes in the combination group and the control (phacoemulsification only) group. METHODS: This retrospective case–control study included 36 eyes with cataract and medically controlled open-angle glaucoma with IOP < 21 mmHg and 100 nonglaucomatous eyes with cataract. Data were collected preoperatively and for 6 months postoperatively. Data included IOP, number of glaucoma medications, corrected distance visual acuity, and mean absolute error (MAE) from target refraction, and astigmatic vector analysis. Surgical success for the combination group was defined according to three criteria: (A) IOP < 15 mmHg without medication, (B) IOP < 18 mmHg without medication, and (C) IOP < 18 mmHg with or without medication. RESULTS: In the combination group, mean IOP was reduced from 15.1 ± 2.9 mmHg to 12.5 ± 2.0 mmHg, and the mean number of medications decreased from 1.9 ± 1.0 to 0.4 ± 0.8 at postoperative 6 months (both P < 0.001). Surgical success rates were 77.8%, 83.3%, and 97.2% at 6 months by criteria A, B, and C, respectively. Mean IOP was reduced from 14.3 ± 2.7 mmHg to 13.1 ± 2.1 mmHg at 1 month in the control group (P < 0.001). The MAE was 0.33 ± 0.26 D, and 83.3% of eyes had spherical equivalent difference within 0.50 D in the combination group (0.38 ± 0.33 D and 76.0% in the control group; P = 0.309 and P = 0.363, respectively). Preoperative and postoperative centroid values were 0.51 D @ 1° and 0.66 D @ 178°, respectively (0.23 D @ 176° and 0.66 D @ 1° in the control group). There were no statistical differences between the two groups with respect to preoperative and postoperative mean absolute values (P = 0.154 and P = 0.322, respectively). CONCLUSIONS: On the basis of our results using Korean real-world interim experience, iStent® inject with cataract extraction has favorable IOP-lowering effects and minimally impacts refractive outcomes.