A recent study published in Ophthalmology and Therapy demonstrated the 5-year outcomes of the iStent inject (Glaukos Corporation) either in combination with cataract surgery or as a standalone procedure in eyes with open-angle glaucoma (OAG).
Give me some background.
While topical pharmacotherapy to lower intraocular pressure (IOP) has been the mainstay of glaucoma treatment for decades, there are notable limitations:
- Ocular surface disease
- Financial burden to patients
- High rates of nonadherence to treatment regimens
As such: Management of OAG via minimally-invasive surgical interventions like selective laser trabeculoplasty (SLT) and microinvasive glaucoma surgery (MIGS) have become more widespread.
Tell me more about the iStent inject.
The iStent Trabecular Micro-Bypass Stent (Glaukos Corporation) was the first MIGS device to be approved by the FDA—more recently, the second-generation iStent inject also received FDA approval.
How the iStent devices work: Both iterations of the iStent create a patent pathway to bypass the trabecular meshwork (TM) and allow for direct aqueous flow into Schlemm’s canal, thereby decreasing IOP.
- The difference between these two devices: The second-gen iStent inject contains two stents while the first-gen device only had one.
Any comparative research on them?
Yes—conducted by the same investigators of this new study.
This previous study reported significant and safe IOP and medication reductions in both devices.
However: They noted a trend toward greater efficacy and fewer adverse events with the iStent inject system compared to the first-gen system.
Now, talk about the study.
In this long-term retrospective consecutive case series, investigators included OAG patients who received the iStent inject with or without phacoemulsification (combined and standalone subgroups, respectively) between 2018 and 2024.
Who was eligible:
- Patients ≥18 years of age with mild-to-moderate OAG
- Individuals with cataract requiring surgery (for combined subgroup)
- OAG patients with the need for IOP and/or medication reduction
Study outcomes: Mean and proportional analyses of IOP and medications over time.
Talk about the patient population.
The study included 271 eyes of 271 patients (mean age 69 years; 55% women; 40-month mean follow-up [range: 10-79 months]).
More details on the included patients:
- Most eyes in the cohort (93%) were diagnosed with primary OAG (POAG)
- The stage of glaucoma at baseline was mild for 86% of eyes and moderate for 14%
- In total, 79% of eyes received the iStent inject in combination with cataract surgery and 21% of eyes underwent a standalone procedure
Findings?
In the overall population, the mean IOP decreased 16.5% from 16.4mmHg at baseline to 13.7mmHg at last follow-up (p = 0.001).
Moreover: The mean number of medications decreased 72.3% from 2.24 at baseline to 0.62 at last follow-up (p = 0.001).
Tell me more.
IOP reductions were also significant (16.5%) in the combined/standalone subgroups and in the mild/moderate subgroups (p = 0.001 for all).
Further: All subgroups experienced increased proportions of eyes on no topical medications at last follow-up vs. preoperative (p = 0.001 for all).
Expert opinion?
“Reduction in mean medication use was particularly noteworthy in the present study, with two-thirds of eyes not requiring any topical medication at their last follow-up compared to only 1.8% preoperatively,” the study authors highlighted.
Limitations?
These included:
- Retrospective and single-center study design
- No medication washout period
- Study was limited to mild/moderate glaucoma
- Reported medication use was based on routine clinical practice instead of a controlled protocol
- Diurnal IOP measurements were not assessed
- Retinal nerve fiber layer (RNFL) thickness was not measured and analyzed (although visual fields [VF]) were
Take home.
These 5-year real-world findings demonstrated significant and sustained reductions in IOP (16.5%) and topical medication burden (72.3%) following iStent inject with or without cataract surgery in eyes with mild and moderate OAG.
Next steps: Further studies could include:
- Detailed analysis of VF outcomes
- Inclusion of RNFL measurements
- Completion of diurnal IOP measurements
- Comparison of iStent inject implantation without cataract surgery versus cataract surgery alone