Publication Exclusive: Minimally invasive glaucoma surgery increasingly performed by anterior segment surgeons

Anterior segment surgeons are increasingly performing minimally invasive glaucoma surgery in their patients with mild to moderate disease, especially in conjunction with cataract surgery.

“What these procedures have done is brought effective glaucoma surgery into the hands of mainstream cataract surgeons who prior to these procedures did not routinely perform glaucoma surgical procedures,” OSN Technology Board Member Jodi I. Luchs, MD, FACS, said. Moreover, minimally invasive glaucoma surgery (MIGS) “can produce a significant difference in clinical outcomes, reducing intraocular pressure and relieving the need to use topical medications in many cases,” he said.

With anterior segment surgeons embracing MIGS to treat mild to moderate glaucoma, fewer patients would need to be referred to glaucoma specialists for disease progression. As a result, glaucoma surgeons would need to perform fewer heroic procedures on end-stage patients because there would be better control of glaucoma upstream in the disease process, according to Luchs. Patients would also be relieved of the hassle of insurance reimbursement for drops or having to worry about ocular surface problems.

“MIGS can provide more round-the-clock routine pressure lowering without requiring the patient’s input,” Luchs said.

Advantages of MIGS

Another advantage of MIGS is that patients are not excluded from having another glaucoma surgical procedure later, such as trabeculectomy or tube shunt surgery.

“Hopefully, when these patients arrive at the point where they need more invasive surgery, they will not be in such end-stage condition,” Luchs said, noting that MIGS might even improve the success rate of a subsequent intervention. “MIGS may be an adjunct to the pressure-lowering effect of a later procedure,” he said.

Thus far, the Glaukos iStent, a trabecular micro-bypass stent, is the only FDA approved MIGS device for use in cataract surgery. Normally performed after cataract removal, the iStent procedure involves introducing an inserter through the phaco incision, advancing past the pupillary margin and then viewing the angle under high magnification with a gonioprism. Once the trabecular meshwork is engaged, the iStent is gently advanced into Schlemm’s canal.

Because anterior segment surgeons such as Luchs are not used to routinely performing intraoperative gonioscopy, there is a short learning curve to achieve good visualization of the angle for facilitating insertion of the titanium iStent.

“Even if things do not go well during the first few procedures — such as difficulty in implanting with a few passes, the inability to quite get the device to sit properly and causing a little bleeding — the next day the patients look great and do great,” Luchs, who over the past year has implanted the iStent in tandem with cataract surgery in about 100 patients, said.

“With this type of procedure, there is very little downside, quite frankly. There is very little harm you can cause with this device. This definitely provides you some level of comfort,” he said.

Luchs said there are a number of devices in development that will be implanted in the suprachoroidal space and some, such as the iStent, into Schlemm’s canal but with different designs. The iStent inject (Glaukos) is preloaded with two stents in one applicator, and the Hydrus microstent (Ivantis) is a crescent-shaped stent that dilates open Schlemm’s canal. The CyPass micro-stent (Transcend Medical) and the iStent supra (Glaukos) both drain into the subconjunctival space, and the Xen gel implant (AqueSys/Allergan) drains into the subconjunctival space. All are pending FDA approval.

 Click here to read the full cover story published in Ocular Surgery News U.S. Edition, February 25, 2016.