Four-Year Outcomes of Two Second-Generation Trabecular Micro-Bypass Stents in Patients with Open-Angle Glaucoma on One Medication

INTRODUCTION: This study evaluated long-term reductions in intraocular pressure (IOP) and medication following implantation of 2 second-generation trabecular micro-bypass stents (iStent inject(®)) in eyes with open-angle glaucoma (OAG) not controlled on 1 preoperative medication. MATERIAL AND METHODS: In this prospective interventional multi-surgeon study, standalone implantation of 2 iStent inject stents was performed in 57 eyes of 57 subjects with OAG, preoperative IOP of 18–30 mmHg on 1 medication, and preoperative post-washout IOP of 22–38 mmHg. The main outcome measures included the proportions of eyes achieving medication-free IOP ≤18 mmHg, IOP ≤15 mmHg, or ≥20% IOP reduction versus preoperative unmedicated IOP. Assessments included IOP, medications, visual acuity, visual field, pachymetry, complications, and interventions. Subjects were followed for 48 months with follow-up continuing in all eyes. RESULTS: At Month 48 (n=57), 95% of eyes achieved an IOP reduction of ≥20% without medication versus preoperative washout IOP; and although they had eliminated medication, 81% of eyes still had an IOP reduction of ≥20% versus preoperative IOP on 1 medication. Mean 48-month unmedicated IOP decreased by 46% to 13.2±1.6 mmHg vs 24.4±1.3 mmHg preoperatively (p<0.0001), with 95% of medication-free eyes having IOP ≤18mmHg and 82% having IOP ≤15mmHg. Over the course of follow-up, 3 eyes had medication added and 1 eye underwent a secondary glaucoma surgery, and safety parameters were favorable. DISCUSSION: Standalone iStent inject implantation in OAG patients on 1 preoperative medication resulted in average IOP reduction to ≤15 mmHg with the elimination of medication and favorable safety through 48 months. TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT02868190.