Gel stent for glaucoma patients finds 40% reduction in IOP

Take-home message: Implantation of a gel stent for glaucoma studied in Europe led to a 40% reduction in IOP.

Reviewed by Rohit Varma, MD

Los Angeles-A new gel glaucoma stent (Xen45, Allergan/AqueSys) reduced IOP by 40% in a multicenter European study involving 60 eyes, said Rohit Varma, MD.

The stent also reduced the number of medications patients required, said Dr. Varma, Grace and Emery Beardsley professor and chairman, USC Department of Ophthalmology; director, USC Eye Institute, Keck School of Medicine at the University of Southern California, Los Angeles.

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The new gel stent has been developed over the past 10 years. The hydrophilic cyndrical implant is about 6 mm long and is made of porcine gelatin crosslinked with glutaraldehyde. The material has other common medical uses.

The implant is soft compared with other standard implants, Dr. Varma said.

“When inserted in the eye, as you can see on an optical coherence tomography image, it’s soft so it follows the path of the related tissues,” he said.

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The procedure used to insert the device is ab interno and connects the anterior chamber to the subconjunctival space. Before its use, a surgeon inserts a low-dose mitomycin C (MMC) injection to reduce postoperative management issues and decrease the risk for fibrosis. The procedure appears to be more effective with the MMC injection, Dr. Varma said.

The procedure is less invasive than other glaucoma implants, as it does not involve incising and dissecting the conjunctiva, he noted.

Experience in Europe

Experience in Europe

As the implant is not yet approved by the FDA, it is currently used and studied in Europe. In a group of 60 patients with 1-year data, the stent reduced IOP by about 40%, Dr. Varma said.

The preoperative average IOP was 22 mm Hg, and patients were on three medications. The average patient age was 64.2 years old.

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The prospective, nonrandomized, multicenter study included patients with primary open-angle glaucoma, pigmentary glaucoma, and pseudoexfoliation. Patients with primary angle-closure glaucoma and uveitic eyes were excluded. About one-third of patients had a previous trabeculectomy or selective laser trabeculoplasty.

At 1 year, the average IOP was 12.9 mm Hg, and patients were on only one medication.

“So, you do need a medication, just as you do with other glaucoma implants to keep the IOP under control,” he said.

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One patient had an extension of the needle used through the conjunctiva, so the stent had to be implanted into another quadrant, Dr. Varma said.

The only other issue was that 9.5% of patients required needling, especially if they had scarring.

“Overall, it’s a safe procedure and very efficacious (40% reduction of IOP),” he said. “The most common issue is one needs to needle the bleb in less than 10% of eyes.”

Rohit Varma, MD

E: rvarma@usc.edu

This article was adapted from Dr. Varma’s presentation at the 2015 meeting of the American Academy of Ophthalmology. Dr. Varma is a consultant for AqueSys.