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NEW ORLEANS -- Patients with glaucoma who were treated with a microstent during cataract surgery retained benefits over traditional surgery at 5 years, a randomized study found.

Eyes that were treated with the Hydrus microstent, which is designed to lower eye pressure, were less likely than untreated eyes to need subsequent invasive glaucoma surgery (6.4% vs 2.5%; P=0.022) and more likely to be medication-free (66% vs 46%; P<0.001), reported Iqbal "Ike" Ahmed, MD, of the University of Toronto, during the American Academy of Ophthalmology annual meeting.

In addition, rate of visual field loss was 47% lower with the microstent (P=0.014), he noted.

"These data suggest the Hydrus is affecting the course of the disease," Ahmed told MedPage Today prior to his presentation here. "Results like these have not been seen before in this class of glaucoma interventions. We have seen short-term benefits, but now we are increasing our understanding of long-term benefits because we have 5-year clinical trial follow-up data."

According to Ahmed, microstents are roughly the size of an eyelash and are placed in the eye during open-angle glaucoma surgery. The microstent promotes fluid flow through Schlemm's canal, which helps dispose of aqueous humor by transporting it to blood vessels.

Estimates have suggested that as many as 20% of cataract surgery patients also have glaucoma, Ahmed noted. Use of microstents has become more popular in recent years, especially in the U.S.

"The Hydrus and similar glaucoma stents, notably iStent and iStent Inject, have become preferred surgical options for treating mild to moderate primary open-angle glaucoma in patients with visually significant cataracts," David Rooney, MD, an ophthalmologist in Metairie, Louisiana, told MedPage Today.

"A identified moderate-certainty evidence that in patients with mild to moderate open-angle glaucoma, Hydrus plus cataract surgery lowers intraocular pressure better than standalone cataract surgery. The Cochrane review also found moderate evidence that Hydrus was more effective than iStent in the short-term lowering of intraocular pressure," Rooney added.

The current analysis is a 5-year follow-up to the HORIZON study, for which 3-year results were last year. Patients with primary open-angle glaucoma were randomized 2:1 to receive cataract surgery with the Hydrus microstent or surgery alone. At 5 years, 80% of patients (443 of 556) remained in the study.

At the 5-year follow-up, 1.4% of microstent patients experienced device malposition. Obstructive focal peripheral anterior synechiae (PAS) occurred in 5.4% of microstent patients versus none in the surgery-alone group, and non-obstructive focal PAS was more common in the microstent patients (8.7% vs 3.7%). No microstents were removed.

"These procedures are very safe," Ahmed said. "The randomized trials show small incremental risks for microstents beyond cataract surgery alone."

"I would caution other glaucoma surgeons to avoid implanting the device in patients with a history of uveitis. I prefer to block all of my patients before implanting the Hydrus to avoid unwanted movement during the surgery. The most common postoperative complication is focal synechiae obstructing the device's inlet, which often can be treated with a YAG laser," noted Rooney.

As for cost, "microstents are covered by Medicare and most insurance plans," Ahmed said. "The costs range from $1,400 to $1,900, depending on many factors and the area of the country. The procedural cost is offset over time by the reduction in medications, office visits, and future, more invasive, surgeries, as well as other costs to the healthcare system incurred when a patient starts to lose vision."

At my practice, "the Hydrus has become my 'go-to' surgical option for patients with mild to moderate primary open-angle glaucoma and visually significant cataracts," Rooney noted. "In practice, I take my patients off of their antihypertensive drops immediately after Hydrus implantation and monitor whether they still need medication management of their glaucoma, which they usually do not."

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