One-Year Comparative Evaluation of iStent or iStent inject Implantation Combined with Cataract Surgery in a Single Center

Abstract

Introduction: This retrospective consecutive case series assessed 12-month effectiveness and safety of iStent^® or iStent inject^® trabecular micro-bypass implants with cataract surgery in patients with open-angle glaucoma (OAG) in a real-world clinical setting.

Methods: Effectiveness outcomes consisted of intraocular pressure (IOP) reduction; glaucoma medication reduction; proportions of eyes achieving IOP < 18, < 15, or < 12 mmHg; and proportional analysis of medication usage. Safety outcomes included adverse events, secondary surgeries, and best-corrected visual acuity (BCVA).

Results: This evaluation included 58 eyes with OAG (35 iStent, 23 iStent inject), with 96.6% of eyes having mild or moderate glaucoma. Diagnoses included primary open-angle glaucoma (the majority; 72.4%), pseudoexfoliative glaucoma, and pigmentary glaucoma. Baseline mean IOP and medications were statistically comparable between groups: 16.1 ± 3.6 mmHg on a mean of 1.8 ± 0.8 medications in the iStent group, and 16.2 ± 3.1 mmHg on a mean of 1.7 ± 0.8 medications in the iStent inject group. Twelve months after stent-cataract surgery, mean IOP was significantly lower in the iStent inject group than in the iStent group (13.1 mmHg vs. 15.4 mmHg, respectively; p < 0.001), and the percent reduction in IOP from baseline was significantly greater in iStent inject eyes than in iStent eyes (19.1% vs. 4.3% reduction, respectively; p < 0.001). At 12 months postoperative, significantly greater proportions of iStent inject eyes than iStent eyes achieved IOP < 18 mmHg (100% vs. 80.0% of eyes, respectively; p = 0.035), IOP < 15 mmHg (73.9% vs. 34.3% of eyes, respectively; p = 0.003), and IOP < 12 mmHg (26.1% vs. 0% of eyes, respectively; p = 0.002). Meanwhile, both groups achieved significant medication reductions at 12 months vs. baseline (94.1% reduction in iStent inject eyes, p < 0.0001; and 72.2% reduction in iStent eyes, p < 0.0001), with the percent reduction being significantly greater in iStent inject eyes than in iStent eyes (p = 0.023). At 12 months, mean number of medications was significantly lower in iStent inject eyes than iStent eyes (0.1 vs. 0.5 medications, respectively; p = 0.021), and significantly more iStent inject eyes (95.7%) than iStent eyes (71.4%) were off medications entirely (p = 0.021). A similarly high safety profile was observed in both groups.

Conclusion: iStent or iStent inject implantation with cataract surgery resulted in substantial and safe reductions in IOP and medications through 12 months postoperative. Consistent with prior observations, greater efficacy was observed with iStent inject than with iStent.

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

Keywords: Cataract; Glaucoma; Intraocular pressure; Medication; Microinvasive glaucoma surgery (MIGS); Safety; Second-generation; Trabecular micro-bypass; iStent; iStent inject.

Fig. 1

iStent^® and iStent inject^® trabecular micro-bypass stents, with relative dimensions (image courtesy of Glaukos Corp., San Clemente, CA, USA)

Fig. 2

Baseline and month 12 mean intraocular pressure

Fig. 3

Intraocular pressure distribution at 12 months postoperative

Fig. 4

Proportional analysis of intraocular pressure at 12 months postoperative

Fig. 5

Mean number of medications from baseline to 12 months postoperative

Fig. 6

Baseline distribution of number of medications

Fig. 7

Month 12 distribution of number of medications