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. 2015 Nov 3:9:2057-65.
doi: 10.2147/OPTH.S91732. eCollection 2015.

A prospective 3-year follow-up trial of implantation of two trabecular microbypass stents in open-angle glaucoma

Eric D Donnenfeld  1 , Kerry D Solomon  2 , Lilit Voskanyan  3 , David F Chang  4 , Thomas W Samuelson  5 , Iqbal Ike K Ahmed  6 , L Jay Katz  7
Affiliations

A prospective 3-year follow-up trial of implantation of two trabecular microbypass stents in open-angle glaucoma

Eric D Donnenfeld et al. Clin Ophthalmol. .

Abstract

Purpose: To evaluate 3-year safety and intraocular pressure (IOP) following two trabecular microbypass stents in phakic and pseudophakic subjects with open-angle glaucoma (OAG) not controlled on preoperative medication.

Patients and methods: In this prospective pilot study, phakic or pseudophakic subjects with OAG and IOP between 18 mmHg and 30 mmHg on one preoperative topical ocular hypotensive medication underwent medication washout. Thirty-nine qualified subjects with preoperative unmedicated IOP ≥22 mmHg and ≤38 mmHg received two stents. Postoperative examinations were scheduled at Day 1, Week 1, Months 1, 3, 6, and 12, and semiannually through Month 60. Ocular hypotensive medication was considered if postoperative IOP exceeded 21 mmHg. IOP, medication use, and safety were assessed at each visit. Subject follow-up through Month 36 was completed.

Results: Thirty-six eyes (92.3%; 95% confidence interval [CI] 79.1%, 98.4%) achieved the primary efficacy end point of Month 12 reduction in IOP ≥20% from baseline (unmedicated IOP) without ocular hypotensive medication. Four subjects required medication during the Month 36 follow-up period. Mean IOP at 36 months for subjects not taking medication was 15.2 mmHg. At 36 months, subjects sustained mean IOP decrease of 9.1±2.7 mmHg (95% CI 8.0 mmHg, 10.14 mmHg), or 37% IOP reduction, from unmedicated baseline IOP. Compared to preoperative medicated IOP, subjects had mean reduction at Month 36 of 5.5±2.7 mmHg (95% CI 4.5 mmHg, 6.6 mmHg), or 26% reduction. Both measures of IOP reduction were highly significant (P<0.001). Other than one case of early postoperative hyphema that resolved at 1 week, no postoperative adverse events were attributed to stent implantation.

Conclusion: In a pilot study, two trabecular microbypass stents to treat OAG subjects on one preoperative medication provided statistically significant, sustained, and safe reduction of IOP to ≤15 mmHg without medication through 36 months.

Keywords: IOP reduction; MIGS; OAG; iStent; intraocular pressure.

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Figures

Figure 1
Figure 1
Example of iStent locations. Notes: (A) OD (right eye): left stent at 2 o’clock, right stent at 4 o’clock. (B) OS (left eye): left stent at 8 o’clock, right stent at 10 o’clock.
Figure 2
Figure 2
Subject flowchart. Abbreviations: LTF, lost to follow up; M, month.
Figure 3
Figure 3
Proportional analyses of IOP outcomes at annual examinations through Month 36, per protocol population. Notes: IOP values were excluded after secondary surgeries. One subject had cataract surgery after M24 and was excluded from the M36 analyses. Abbreviations: IOP, intraocular pressure; w/o, without; med, medication; M, month.
Figure 4
Figure 4
IOP over time, consistent cohort through Month 36 (n=30). Notes: IOP values were excluded for eyes on postoperative medication and after secondary surgeries. One subject had cataract surgery after M24 and was excluded from subsequent statistics. Abbreviations: IOP, intraocular pressure; M, month; SCR, screening; BL, baseline.
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References

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