Long-term Outcomes of a Prospective, Randomized, Double-Masked Study of Micro-Invasive Glaucoma Surgery (MIGS) with Trabecular Micro-Bypass Stent and Cataract Surgery vs. Cataract Surgery Alone

Purpose:Micro-invasive glaucoma surgery (MIGS) involving ab interno implantation of single multiple trabecular micro-bypass stents during cataract surgery has been shown to be significantly more effective incontrolling IOP than cataract surgery alone.[1],[2] This reports on long-term follow-up of a prospective, randomized, double-masked evaluation of iStent implantation in conjunction with cataract surgery (treatment group) vs. cataract surgery alone (control group) in eyes with primary open-angle glaucoma. [1].Fea, AM. Phacoemulsification versus phacoemulsification with micro-bypass stent implantation in primary open-angle glaucoma. J Cataract Refract Surg 2010; 36:407-412. [2]. Samuelson TW, Katz LJ, Wells JM, et al. Randomized evaluation of the trabecular micro-bypass stent with phacoemulsification inpatients with glaucoma and cataract. Ophthalmology 2011;118:459-467. Methods:Ten eyes in the treatment group and 14 eyes in the control group were evaluated. Mean follow-up was 55.4 months (SD 8.9). At this visit, evaluations included IOP, BCVA, ocular hypotensive medications,slit-lamp exam, fundus/optic nerve exam, gonioscopy, and assessment of secondarysurgeries. Subjects were then washed out of ocular hypotensive medications and re-examined one month later for evaluation of IOP. Results:In this subset of eyes with long-term follow-up, pre-operative IOP in the treatment group was 17.8 mmHg (SD 2.7) on an average of 1.9 medications. At an average of 51.3 months post-op, IOP was 15.9 mmHg (SD 2.3) on an average of 0.5 medications. Following washout at 52.3 months, IOP was 17.5 mmHg (SD 2.3) in the treatment group. .Preoperative IOP in the control group was 15.7 mmHg (SD 2.8) on an average 2 medications. At an average of 58.3 months post-op, IOP in the control group was 17.0 mmHg (SD 2.5) on an average of 1 medication. Following washout, IOP was 20.1 mmHg (SD 4.8) inthe control group. Average preoperative BCVA was 20/46 in the treatment group and 20/55 in the control group. Last reported BCVA was 20/26 in both groups. No secondary surgical interventions were reported and no other adverse events or untoward findings were reported in either group. Conclusions:Implantation of a single stent in conjunction with cataract surgery resulted in long-term IOP control with a reduced medication burden through four years postoperative that was more effective than cataract surgery alone and with a safety profile similar to that of cataract surgery alone.