Prospective, Non-randomized, 36-Month Study of Second-Generation Trabecular Micro-Bypass Stents with Phacoemulsification in Eyes with Various Types of Glaucoma

Abstract

IntroductionThe aim of this study was to assess 36-month outcomes after cataract surgery and implantation of two second-generation trabecular micro-bypass stents (iStent inject, Glaukos Corporation, San Clemente, CA, USA) into eyes with predominantly primary open-angle glaucoma (POAG) or pseudoexfoliative glaucoma (PEX).MethodsThis prospective, non-randomized, consecutive cohort study included eyes with POAG (n = 60), PEX (n = 15), appositional narrow-angle (n = 4), pigmentary (n = 1), or neovascular (secondary) (n = 1) glaucoma and cataract requiring surgery. All eyes (n = 81) underwent ab interno iStent inject implantation following cataract surgery. Effectiveness endpoints through 36 months included intraocular pressure (IOP), number of medications, and proportion of eyes with ≥ 20% IOP reduction, IOP ≤ 18 mmHg, and IOP ≤ 15 mmHg. Safety measures included corrected distance visual acuity (CDVA), adverse events, and secondary surgeries. Outcomes were evaluated for the overall cohort, and for the POAG and PEX subgroups.ResultsPreoperatively, 32.1% of eyes had undergone prior glaucoma surgery, 56% were on 3–4 medications, and 1 eye (1%) was medication-free. At 36 months postoperatively, mean IOP reduced by 37% (14.3 ± 1.7 mmHg versus 22.6 ± 6.2 mmHg preoperatively), and mean medication burden decreased by 68% (0.8 ± 0.9 versus 2.5 ± 1.1 medications preoperatively). IOP reduced by ≥ 20% in 78% of eyes; 100% of eyes reached IOP ≤ 18 mmHg and 71% reached ≤ 15 mmHg. Medication burden reduced considerably: 22 eyes (54%) were medication-free compared to 1 eye (1%) preoperatively; 1 eye (2%) required ≥ 3 medications compared to 45 eyes (56%) preoperatively; and 92.7% of eyes required reduced medications postoperatively. From 3 through 36 months, mean IOP remained ≤ 15.0 mmHg, and mean number of medications remained ≤ 0.9. Outcomes in the POAG and PEX subgroups included 33% and 32% lower IOP, and 68% and 64% fewer medications, respectively. iStent inject showed a favorable safety profile, including no intraoperative complications, minimal adverse events, and a stable CDVA.ConclusionThis real-world cohort of eyes with various types of glaucoma and considerable disease burden exhibited durable and safe IOP and medication reductions through 36 months following iStent inject implantation with cataract surgery. Outcomes were similarly beneficial in eyes with POAG and PEX.FundingArticle processing charges were funded by Glaukos Corporation (San Clemente, CA, USA).

Second-Generation Trabecular Micro-Bypass Stents as Standalone Treatment for Glaucoma: A 36-Month Prospective Study

“…It is noteworthy that iStent inject had a positive effect in these formerly treatment-resistant eyes. This treatment effect is consistent with prior studies showing benefit of this technology in various stages of glaucoma, from mild to advanced [40][41][42][43][44][45][46][47][48][49][50][51]. It also suggests that iStent inject may have a viable role in settings different from those typically considered for MIGS procedures: specifically, it may be considered not just in mild-to-moderate glaucoma as a primary surgery, but also in refractory eyes that have progressed despite previously undergoing more invasive surgery.…”

“…1-2). In studies both with and without cataract surgery, and in both investigational and real-world settings, the ab interno-implanted iStent inject has demonstrated clinically significant reductions in IOP and medications over the long term [40][41][42][43][44][45][46][47][48][49][50][51]. These performance outcomes have been accompanied by favorable safety and a correspondingly advantageous benefit-to-risk profile.…”

Prospective, Randomized, Controlled Pivotal Trial of an Ab Interno Implanted Trabecular Micro-Bypass in Primary Open-Angle Glaucoma and Cataract

“…23 Finally, an independent report of iStent inject implantation in conjunction with cataract surgery showed a mean IOP of 14.8 mmHg on an average of 0.8 medications at 24 months. 31 Although direct comparisons are not possible between the current work and this earlier singlesurgeon report, it is possible that continued U.S. surgical experience with this technology beyond the work included in this pivotal trial may show additional IOP reduction.…”

Reply

“…In studies outside the confines of RCTs, the IOP reduction of iStent inject has been even more marked. 4,5 MIGS RCTs produce clinical situations rarely encountered outside controlled trials, specifically washedout IOP both preoperatively and postoperatively. Comparing results of stringently controlled trials with less controlled studies with different requirements for preoperative IOP and medication washout is simply without merit.…”