Surgical Outcomes of Combined Trabecular Microbypass (iStent inject® W) and Phacoemulsification for Treatment of Controlled Primary Open-Angle Glaucoma in Korean Patients

Purpose: To report the interim intraocular pressure (IOP)-lowering efficacy of combined trabecular microbypass stenting (iStent inject ® W) and phacoemulsification (Combo group) and to compare refractive changes between the Combo and Control (cataract extraction only) groups.Methods: This retrospective case-control study included 39 eyes with cataracts and controlled primary open-angle glaucoma (POAG) with IOP ≤ 21 mmHg as well as 100 non-glaucomatous eyes with cataracts.Mean IOP; number of anti-glaucoma medications; refractive outcomes of visual acuity, mean absolute error, and astigmatic vector analysis using the ASCRS double-angle plot were analyzed.Success in the Combo group was defined according to the following three criteria: (A) decreased medication number, (B) IOP reduction > 20%, and (C) decreased medication number and IOP reduction > 20%.Results: In the Combo group, the mean IOP was reduced from 15.5 mmHg with 1.6 bottles of medication to 12.7 mmHg with 0.2 bottles at 6 months postoperatively (both p < 0.001).Surgical success rates according to criteria A, B, and C were 92.3, 38.5, and 33.33%, respectively.Overall, 69.2% of eyes achieved a final IOP ≤ 18 mmHg, 48.7% were ≤ 15 mmHg, and 35.9% ≤ 12 mmHg without medication, whereas 92.3% of eyes achieved IOP < 18 mmHg with or without medication.The mean absolute error was 0.35 ± 0.30 D (vs.0.38 ± 0.33 D in control), and 76.9% of eyes in the Combo group had a spherical equivalent difference within 0.50 D (vs.76.0% in control).Preoperative and postoperative centroid values were 0.31 D @ 168° ± 1.15 D and 0.70 D @ 1° ± 0.86 D, respectively.There were no statistical differences between the 2 groups with respect to preoperative and postoperative mean absolute values (p = 0.918 and p = 0.269, respectively).There were no vision-threatening complications, although mild complications of IOP spikes (n = 5, 12.8%), hyphemas (n = 4, 10.3%), and stent obstruction by the iris (n = 2, 5.1%) were documented.Conclusions: In terms of number of medications, the Combo procedure with iStent inject ® W and phacoemulsification for controlled POAG led to favorable modest IOP-lowering effects and refractive outcomes.