Hydrus Microstent for Glaucoma

The strongest clinical evidence supporting the Hydrus Microstent comes from the HORIZON trial, one of the largest and longest-running MIGS pivotal studies.

The HORIZON trial was a prospective, multicenter, randomized controlled study that enrolled 556 patients with mild to moderate open-angle glaucoma who were also undergoing cataract surgery. Patients were randomly assigned to receive either the Hydrus Microstent combined with cataract surgery or cataract surgery alone. This design allowed researchers to isolate the pressure-lowering effect of the Hydrus device itself.

At two years, the data that led to FDA approval showed that a significantly higher proportion of patients in the Hydrus group achieved a clinically meaningful reduction in intraocular pressure compared to cataract surgery alone. Patients who received the Hydrus Microstent were also more likely to be free of glaucoma medications at the two-year mark.

Approximately 80 percent of the original study participants were followed out to five years. Long-term data confirmed that the Hydrus Microstent maintained its pressure-lowering effect over this period with no sight-threatening adverse events attributed to the device. A post hoc analysis also found a slower rate of visual field progression in eyes that received the Hydrus, suggesting a protective benefit for long-term vision preservation. At four years, patients who received the Hydrus were three times less likely to require additional incisional glaucoma surgery compared to those who had cataract surgery alone.

The rate of serious adverse events in the Hydrus group (3.5 percent) was comparable to the cataract-surgery-only group (4.3 percent) at five years. One notable finding was a higher rate of peripheral anterior synechiae (PAS), a type of scar tissue formation in the drainage angle, in the Hydrus group (14.6 percent versus 3.7 percent), though this did not lead to clinical complications. Endothelial cell density loss was slightly higher in the Hydrus group at three months due to the additional surgical manipulation, but the rate of change beyond that point was not significantly different between groups.

The Hydrus Microstent is FDA-approved for adults with mild to moderate primary open-angle glaucoma who are undergoing cataract surgery. Ideal candidates typically have elevated eye pressure that is not adequately controlled with medications alone or who want to reduce their medication burden. Patients with advanced glaucoma, angle-closure glaucoma, or certain other eye conditions may be better served by alternative procedures such as the XEN Gel Stent or traditional glaucoma surgery.

Most patients recover quickly because the Hydrus is implanted through the same incision used for cataract surgery. Visual recovery from the cataract component typically occurs within a few days, while eye pressure stabilization may take several weeks. Most patients can resume normal daily activities within one to two days and more vigorous activities within two weeks.

Many patients experience a significant reduction in their glaucoma medication use after Hydrus implantation. In the HORIZON trial, a higher proportion of patients in the Hydrus group were medication-free compared to those who had cataract surgery alone, and this benefit persisted through five years of follow-up. However, some patients may still need one or more drops to keep their pressure at a safe level, and your medication plan will be tailored to your individual response.

The Hydrus Microstent has a favorable safety profile supported by five years of clinical trial data. Potential risks include temporary increases in eye pressure, mild inflammation, device obstruction, and peripheral anterior synechiae. Serious complications such as infection or device migration are rare, and the rate of serious adverse events in the HORIZON trial was comparable between the Hydrus and cataract-surgery-only groups.

Because the Hydrus Microstent is FDA-approved and performed during cataract surgery, it is typically covered by Medicare and most private insurance plans. Coverage may vary depending on your specific plan, so we recommend confirming your benefits with your insurance provider before scheduling the procedure. Our team can help you understand what to expect regarding costs and coverage.

The HORIZON trial demonstrated sustained pressure reduction and medication-free rates through five years, which represents the longest follow-up data available from any MIGS pivotal trial. Because the device is a permanent implant that scaffolds the eye's natural drainage system, its structural benefit is designed to be long-lasting. Our glaucoma specialists will continue to monitor your eye pressure over time to ensure your treatment plan remains effective.