April 2018

COVER FEATURE

Intersection of refractive surgery and MIGS
What’s coming in refractive surgery and MIGS?


by Rich Daly EyeWorld Contributing Writer


 


The iStent, if properly positioned, is stable and easy to evaluate with a gonio lens postop.
Source: Gary Wortz, MD


Gonio picture of the CyPass post-implantation
Source: Sean Ianchulev, MD

Surgeons share what they think the future holds for refractive surgery and MIGS

Microinvasive glaucoma surgery (MIGS) is “coming of age” as a lifestyle treatment—similar to refractive lens surgery’s earlier evolution.
That was the recent assessment of George Waring IV, MD, founder and medical director, Waring Vision Institute, Mt. Pleasant, South Carolina, who noted that they are complimentary procedures and both have a lifestyle component.
“People seek out refractive lens procedures to reduce their need for bifocals and reading glasses,” Dr. Waring said. “With MIGS it is not only the opportunity to lower pressure to prevent the worsening of glaucoma, but there is also a lifestyle opportunity, so in many cases they may need less drops or no drops at all. That conversation resonates with patients.”
Benefits of MIGS include eliminating or reducing the need for topical IOP-controlling drops, which can cause chronic issues with long-term use. Chronic conditions include ocular surface disease and cosmetically significant periorbital atrophy of fat and sunken orbits.
“There’s a convenience factor as well as potential cosmetic considerations like the eyes not being as red, and long-term avoidance of some of the other issues associated with drops, such as the periorbital fat atrophy,” Dr. Waring said.
Gary Wortz, MD, Lexington, Kentucky, said pairing multifocal IOLs—not refractive surgery generally—and MIGS is like putting an upgraded engine on an old transmission in a car. 
“In order to truly enjoy the benefits of refractive surgery, we need a healthy eye,” Dr. Wortz said. “While MIGS may mitigate disease, we are still talking about an eye at risk for significant loss of vision over time. I think the correction of astigmatism is extremely helpful in these patients. However, I would still consider glaucoma a relative contraindication to multifocality.”
Moving into the future, ophthalmology needs to address refractive challenges of the glaucoma patient who has significant demands in terms of contrast sensitive and IOL optimization, said Sean Ianchulev, MD, professor of ophthalmology, New York Eye and Ear Infirmary, Icahn School of Medicine at Mount Sinai, New York.
“We need a cohesive refractive glaucoma surgery solution where we provide both IOP control and a maximized refractive outcome,” Dr. Ianchulev said. 

New technology

Among the new MIGS technology that most interests Dr. Wortz is the Hydrus Microstent (Ivantis, Irvine, California). With the iStent (Glaukos, San Clemente, California) he has had mixed results—likely because of his inability to target collector channels—but the Hydrus is a much larger stent that gives him a better chance of putting it in the right spot.
Additionally, suprachoroidal and bleb-based devices are still finding their place and have a big potential upside, he said.
“I’m taking a wait-and-see-approach to them at the moment, but I am excited about their potential,” Dr. Wortz said.
As the developer of the CyPass Micro-Stent (Alcon, Fort Worth, Texas), Dr. Ianchulev is excited about use of the device in a supraciliary approach, which shows a higher capacity of outflow accommodation than the trabecular space and has a similar safety profile. “I hope that we will soon see trials of supraciliary stenting as a standalone procedure in pre-trab patients, where we can see MIGS devices open more options for glaucoma patients outside the limitations of concomitant cataract surgery,” he said.
Dr. Waring highlighted the “fabulous safety and efficacy profile” of the Hydrus, the next generation iStent inject device, and the XEN Gel Stent (Allergan, Dublin, Ireland). The iStent inject includes two stents preloaded in an auto-injection mechanism.
“All of these—particularly the Hydrus and the XEN—open up the door to treat more advanced states of glaucoma and provide the opportunity to truly help people get off eye drops,” Dr. Waring said.
Among the lingering concerns Dr. Waring has about the technology is the likelihood that they can delay refractive benefits in combined procedures when compared to a standalone refractive IOL surgery.
“Although we routinely combine MIGS and presbyopia-correcting IOLs, for example, the patient counseling is important because they are excited about their refractive outcomes, but we have to explain to them that first we are doing a medical procedure that may slow down their recovery if we combine it with a MIGS procedure,” Dr. Waring said.
Another issue he highlighted is the potential in certain MIGS devices, such as the CyPass, to be associated with a rare myopic or refractive shift. In such cases Dr. Waring would not recommend the use of a presbyopia-correcting IOL.

Femto limits

One technology with expanding applications that appears to have found little benefit so far in the MIGS area is femtosecond laser systems.
Dr. Waring noted that the increasing adoption of femtosecond lasers means the use of the lasers is more common in lens-based surgery that also involves MIGS.
“But we don’t think there are any distinct advantages for MIGS when we are doing this,” Dr. Waring said.
Dr. Ianchulev agreed that femtosecond technology has not proven highly applicable to the glaucoma space and is still searching for clinical utility.
“New solutions are needed,” he said.

IOL benefits

Future intraocular lens developments that might benefit the MIGS space include utilizing them to hold IOP telemetry devices or as drug delivery device, Dr. Wortz said.
“We have not properly leveraged the inert space inside the lens capsule to even a fraction of its potential,” Dr. Wortz said.
The potential for implanted IOP monitors is exciting to Dr. Ianchulev. “Continuous IOP monitoring is a perfect piggyback technology for IOLs and MIGS. This could open new advanced IOL technology and even premium surgical options for glaucoma patients,” he said.
“For the glaucoma patient, it is important to nail down IOL power as precisely as possible and to come up with better premium options for glaucoma patients who have lower contrast sensitivity,” Dr. Ianchulev said. “This is where I think new solutions will start to emerge.”
Modular IOLs, such as the lens from Omega Ophthalmics (Lexington, Kentucky), can offer a potential intracapsular space for intraocular pressure sensors, such as microchips, Dr. Waring said.
“Now, not only are we helping the glaucoma with the MIGS, but we may be implanting a microsensor for intraocular pressure at the same time,” he said.
Such lenses would allow self- monitoring at home and provide real time information on diurnal fluctuations, which might not get caught at the clinic.
“They may have high diurnal IOPs at a certain time of day when they are not at the clinic where we may need to consider an alternative to help them further,” Dr. Waring said.

Editors’ note: Dr. Waring has financial interests with Allergan, Glaukos, Ivantis, and Omega Ophthalmics. Dr. Ianchulev has financial interests with Alcon, Eyenovia (New York), and Iantech (Reno, Nevada). Dr. Wortz has financial interests with Allergan, Johnson & Johnson Vision (Santa Ana, California), and Omega Ophthalmics.

Contact information

Ianchulev
: tianchul@privatemedicalequity.com
Waring: gwaring@waringvision.com
Wortz: 2020md@gmail.com

What’s coming in refractive surgery and MIGS? What’s coming in refractive surgery and MIGS?
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