One-Year Outcomes of Second-Generation Trabecular Micro-Bypass Stents (iStent Inject) Implantation with Cataract Surgery in Different Glaucoma Subtypes and Severities

Abstract

Purpose: To assess the 1-year efficacy and safety of the implantation of two second-generation trabecular micro-bypass stents (iStent Inject^®) with concomitant cataract surgery in various subtypes and severities of glaucoma.

Methods: This single-surgeon, consecutive case series from a Canadian academic ophthalmology center included subjects with cataract, glaucoma, and the need to reduce intraocular pressure (IOP) and/or medications. The 12-month outcomes included mean IOP and medication burden as well as the proportions of eyes with IOP ≤ 18, ≤ 15, and ≤ 12 mmHg compared to baseline. Other measures included corrected distance visual acuity (CDVA), cup-to-disc ratio (CDR), visual field mean deviation (VF MD), retinal nerve fiber layer (RNFL) thickness, ganglion cell inner plexiform layer (GCIPL) thickness, and adverse events.

Results: In 118 eyes, mean IOP reduced from 17.00 ± 3.82 mmHg preoperatively to 13.97 ± 2.65 mmHg at the 12-month follow-up mark (17.8% reduction, p < 0.001), and mean medication burden decreased from 2.31 ± 1.33 preoperatively to 1.03 ± 1.10 medications (56% reduction, p < 0.001). After 12 months, 93% of eyes achieved IOP ≤ 18 mmHg (versus 69% preoperatively), 70% of eyes achieved IOP ≤ 15 mmHg (versus 42% preoperatively), and 29% of eyes achieved IOP ≤ 12 mmHg (versus 7% preoperatively). For all eyes, topical medications were either maintained or decreased from baseline, with ≥ 1 medication eliminated from the preoperative regimen for 83% of eyes and ≥ 2 medications eliminated for 36% of eyes. Visual acuity improved significantly, consistent with expectations for cataract surgery, while CDR, VF MD, and RNFL and GCIPL thicknesses remained stable. Safety was favorable, with no intraoperative complications and few transient adverse events postoperatively.

Conclusion: iStent Inject implantation with cataract surgery safely reduced IOP and medication burden in a real-world clinical population with mild to severe glaucoma, and stabilized visual field, as well as RNFL and GCIPL thicknesses on OCT.

Funding: The Rapid Service Fees were funded by Glaukos Corporation.

Keywords: Cataract; Glaucoma; Micro-invasive glaucoma surgery (MIGS); Stent; Trabecular micro-bypass; iStent Inject.

Fig. 1

Change in average intraocular pressure (n = 118). Following cataract surgery combined with implantation of iStent Inject, mean intraocular pressure significantly decreased and was maintained throughout follow-up (p < 0.001). Asterisk signifies statistical differences at p < 0.05; bars demonstrate standard error of the mean; IOP intraocular pressure

Fig. 2

Percentages of eyes with IOP ≤ 18, ≤ 15, and ≤ 12 mmHg (n = 118) preoperatively and at 1-year follow-up. Solid bars and diagonally hashed bars represent preoperative and 1-year follow-up data, respectively. IOP intraocular pressure

Fig. 3

Change in mean number of glaucoma medications (n = 118). Following cataract surgery combined with implantation of iStent Inject, the mean number of medications significantly decreased, and this was maintained throughout follow-up (p < 0.001). Asterisk signifies statistical differences at p < 0.05; bars demonstrate standard error of the mean

Fig. 4

Proportions of the eyes with reductions of ≥ 0, ≥ 1, or ≥ 2 medication(s) at t 12 months. Solid bars represent the 1-year follow-up data. Med medication