Minimally invasive bleb surgery (MIBS) may be poised to occupy a broader role in glaucoma care, with multiple devices in development that could eventually expand treatment options beyond the operating room and, potentially, into the clinic. These MIBS technologies could help narrow the long-standing gap between the efficacy of traditional filtering surgery and the safety profile of angle-based MIGS, said Ian F. Pitha, MD, PhD, during a presentation at the American Glaucoma Society’s annual meeting in Rancho Mirage, California.
Dr. Pitha, a glaucoma specialist and associate professor at the John A. Moran Eye Center at the University of Utah in Salt Lake City, framed MIBS as a response to a familiar clinical compromise. “Traditionally, our most effective ways of reducing intraocular pressure (IOP) have involved a tradeoff between efficacy and safety,” he said. Filtering procedures such as trabeculectomy or tube shunts can provide durable pressure lowering, but at the cost of higher risk and prolonged postoperative care. By contrast, angle-based minimally invasive glaucoma surgeries (MIGS) offer improved safety and faster recovery, but “they don’t really robustly lower pressure,” limiting their use in patients who have advanced disease.
Dr. Pitha noted that MIBS is intended to bridge that divide. “The goal of MIBS is to achieve IOP reduction that approaches our more successful surgeries like trabeculectomies or tubes, but does so with enhanced safety, a quicker postoperative recovery for our patients, and a more streamlined surgical approach,” he said. The concept, he added, is particularly appealing for patients at highest risk of vision loss who may benefit from stronger pressure lowering without the full burden of traditional filtering surgery.
In the United States, the most familiar MIBS option has been the Xen 45 gel stent (Allergan/AbbVie). While studies have shown sustained IOP reduction, outcomes have generally not matched those of trabeculectomy. A variant with a larger lumen, the Xen 63, may offer incremental advantages, he noted, but it has not yet been improved for use in the United States.
Other options also remain investigational domestically. The PreserFlo MicroShunt, used internationally for more than a decade, is now in US pivotal trials under the direction of Glaukos. “It works, and I’m very happy that Glaukos has picked up clinical development,” Dr. Pitha said, adding that US availability could come within the next few years.
Earlier-stage devices include the Calibreye titratable shunt (Myra Vision), which has reported encouraging 12-month safety and efficacy data outside the United States, and the VisiPlate aqueous shunt (Avisi Technologies), which is currently enrolling US patients in the SAPPHIRE trial. Nonimplant approaches are also emerging, such as Aqualumin from PLU Ophthalmics, which creates a scleral outflow tract using a dual-needle system. Another company, Hexiris, is also working on a MIBS solution, he said.
“There are a lot of devices that are in development,” Dr. Pitha concluded. “Hopefully some of them will reach the clinic for us.” GP