May 2019

IN FOCUS

Technology & Innovation
Giving new glaucoma technology its time in the spotlight


by Vanessa Caceres EyeWorld Contributing Writer


Successful trabeculectomy with a low and diffuse
filtering bleb and stable IOP of 8 to 10 mm Hg for
more than 10 years
Source: Lou Cantor, MD

“Data supporting these
newer approaches to
therapy will require time before we can best assess which procedures are
indicated for which
individual patients.”
—Louis Cantor, MD

 

The subspecialty of glaucoma is now teeming with new technology to assist with surgical procedures, IOP management, and diagnostics. However, just like any new technology, surgeons must constantly monitor for better usage, cost, and effectiveness. Here’s a rundown of some of the new glaucoma technology that surgeons are finding helpful.

Management through MIGS

Innovation for microinvasive glaucoma surgery (MIGS) has flourished in recent years, with a few newer MIGS devices in particular getting praise and attention.
“In terms of devices that target the trabecular meshwork, the newly designed iStent inject [Glaukos] comes with two preloaded devices on one injector that are smaller than the original model,” said Allison Angelilli, MD. “They are injected into the nasal trabecular meshwork and have a central lumen with four outflow ports designed to deliver aqueous fluid directly into Schlemm’s canal.”
Glaukos also has other iStent innovations on the horizon, such as the Supra and the
infinite, Dr. Angelilli said.
Like iStent inject, the Hydrus Microstent (Ivantis) has encouraging pressure-lowering and medication reduction results when combined with cataract surgery, Dr. Angelilli said.
“They are fairly straightforward to implant, although there is a learning curve as with most MIGS,” said Valerie Trubnik, MD, about the Hydrus. “The Hydrus, much like the iStent, allows the patient to have a fast visual recovery and the opportunity to get off of one or two drugs that they were on before.”
Among other MIGS choices, the XEN Gel Stent (Allergan) bypasses the trabecular outflow by creating a direct pathway for aqueous egress through a microscopic flexible stent implanted into the subconjunctival space, Dr. Angelilli said. Even though it theoretically carries the risks of an aqueous bypass procedure like trabeculectomy, it lessens the risk for hypotony and delayed visual recovery. Many glaucoma surgeons have refined their XEN technique by using an ab externo approach that delivers the stent from the subconjunctival space into the anterior chamber, said Nathan Radcliffe, MD. The idea behind the approach is to lessen initial challenges with the XEN. The new approach has made a big difference for Dr. Radcliffe. “Once I developed my new technique, I started using the XEN 10 times as often,” he said.
This new use of the XEN also demonstrates how glaucoma surgeons likely will continue to refine their use of any new technology that reaches their hands, Dr. Radcliffe said.
Another MIGS technology approved in Europe but not yet in the U.S. is the InnFocus MicroShunt Glaucoma Drainage System (Santen), which bypasses aqueous into the subconjunctival space. “It shows promise as an effective addition in the MIGS space due to [its] thermoplastic elastomeric material,” Dr. Angelilli said.

IOP management

“Precise measurement of IOP is the cornerstone of glaucoma management,” Dr. Angelilli said. However, the occasional in-office measurements are less than ideal for management, particularly in patients with glaucomatous progression. That’s why both new devices to measure IOP and new drugs to help control IOP are always needed.
Patient adherence to eye drop use is always a major struggle, so many glaucoma surgeons are excited about newer ways to approach IOP management, including punctal plugs and injections.
“Data supporting these newer approaches to therapy will require time before we can best assess which procedures are indicated for which individual patients,” said Louis Cantor, MD.
Although Dr. Cantor thinks that the majority of glaucoma patients will continue to use topical drops, he also noted that sustained release drug delivery approaches could enhance compliance and reduce the burden of therapy.
Punctal plugs and injectable implants that deliver medication to patients could help with the dilemma of patient compliance, Dr. Trubnik said. “We already have plugs on the market with steroids but not for glaucoma drugs,” she said. As one example, Ocular Therapeutix has a travoprost intracanalicular insert that is at the Phase 3 stage (the company also has a travoprost implant at the Phase 1 stage). “If explained the right way, I think a lot of patients would agree to [punctal plugs],” she said. Mati Therapeutics is also developing a punctal plug delivery system for latanoprost and other agents, Dr. Cantor said.
However, the bigger concern will be whether Medicare or third-party payers will cover the cost involved with newer drug delivery devices, Dr. Trubnik said.
When it comes to implantable drug delivery systems, such as iDose, one concern would be whether it is worthwhile to have patients take multiple trips to the OR to implant devices that deliver medications, considering a possible increased infection risk—and how to handle patients who don’t return for follow up if the technology is not biodegradable.
Another consideration among the technology options is a continuous pressure monitoring device that would provide 24-hour IOP monitoring. “Their widespread use has not been adopted, although this is an area of interest in the glaucoma community,” Dr. Angelilli said.
There are also newer therapies for glaucoma patients to consider, such as the Rho-kinase inhibitor netarsudil (Rhopressa, Aerie Pharmaceuticals) and the fixed combination of netarsudil and latanoprost (Roclatan, Aerie Pharmaceuticals), which was approved by the U.S.
FDA earlier this year. Latanoprostene bunod (VYZULTA, Bausch + Lomb) was introduced in 2018, Dr. Cantor added. It’s a prostaglandin analog that releases nitric oxide and that may convey vasoactive effects, he said.
For in-office IOP measurements, a new device on the horizon called the Correcting Applanation Tonometer Surface (CATS) prism (CATS Tonometer) has a newly designed and engineered tonometer prism tip for Goldmann applanation tonometry, Dr. Radcliffe said. The new tip will help the tonometer limit bias from corneal thickness, curvature, hysteresis, and the tear film. “It’s going to be easy for all of us to adopt the CATS prism and patients will benefit quickly,” he said.

Diagnostic technology

One advance within glaucoma diagnostic technology is the ability to better integrate OCT structural data with functional data to help with clinical decision-making, Dr. Cantor said. The use of OCT angiography could help specialists make an earlier glaucoma diagnosis, Dr. Trubnik said.
Dr. Radcliffe said that corneal hysteresis may play a greater role in glaucoma diagnostic management going forward, specifically to indicate which eyes would do well with therapy such as MIGS and which eyes may require additional therapies.

At a glance

• Newer MIGS devices such as the iStent inject, Hydrus, and XEN are getting praise from glaucoma surgeons for helping to lower IOP and reduce medication use.
• A variety of approaches may help with IOP management, including newer drugs as well as devices that can release medications, such as punctal plugs.
• Some concerns with newer technology include cost,
coverage, frequency of insertion, and how to handle patients lost to follow up.
• Newer approaches for glaucoma diagnostic
technology include OCT angiography and the use of corneal hysteresis to help predict patient success with various treatments.

Contact information

Angelilli: aangelilli@ocli.net
Cantor: lcantor@iu.edu
Radcliffe: drradcliffe@gmail.com
Trubnik: vtrubnik@ocli.net

About the doctors

Allison Angelilli, MD

Clinical assistant professor of ophthalmology
Donald and Barbara Zucker School of Medicine
Hofstra University/Northwell
Hempstead, New York

Louis Cantor, MD
Jay C. and Lucile L. Kahn Chair of Glaucoma Research and Education
Eugene and Marilyn Glick
Eye Institute
Indiana University School
of Medicine
Indianapolis

Nathan Radcliffe, MD
New York Eye and Ear Infirmary
New York

Valerie Trubnik, MD
Ophthalmic Consultants of Long Island

Financial interests
Angelilli: None
Cantor: Carl Zeiss Meditec, Santen, Allergan, Mati Therapeutics
Radcliffe: Aerie Pharmaceuticals, Glaukos
Trubnik: None

Giving new glaucoma technology its time in the spotlight Giving new glaucoma technology its time in the spotlight
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