August 2018


Glaucoma's armamentarium
MIGS in relation to traditional glaucoma surgery

by Ellen Stodola EyeWorld Senior Staff Writer/Digital Editor

InnFocus MicroShunt 1 year after placement; IOP is 14 mm Hg on no medications; preop IOP was 26 mm Hg on three medications
Source: Marlene Moster, MD

Experts discuss how MIGS may decrease the role of traditional glaucoma procedures

With MIGS procedures expanding and the utility of new devices being explored, glaucoma surgeons now have a variety of options for the entire spectrum of glaucoma. Valerie Trubnik, MD, Ophthalmic Consultants of Long Island, Lynbrook, New York, and Marlene Moster, MD, Wills Eye Hospital, Philadelphia, discussed how this has changed their practice and the different procedures that they use.

Reducing traditional glaucoma surgeries

Dr. Trubnik said she has been able to cut back on the number of traditional glaucoma surgeries she performs, and she has recently transitioned most of her trabeculectomies to the XEN Gel Stent (Allergan, Dublin, Ireland) procedure. She noted that her use of tubes has stayed relatively the same because she generally reserves this option for someone with a failed trabeculectomy or XEN stent.
In her practice, Dr. Trubnik uses the iStent (Glaukos, San Clemente, California), endoscopic cyclophotocoagulation (ECP), the Kahook Dual Blade (KDB, New World Medical, Rancho Cucamonga, California), the XEN, and the CyPass (Alcon, Fort Worth, Texas).
Dr. Moster agreed that she has cut back on the number of traditional glaucoma surgeries she does.
“With the available MIGS, we’ve been able to cut down the triple procedures,” Dr. Moster said. “Where before we had mostly tubes and trabs, now we can operate sooner with decreased risk.”
Dr. Moster said she is currently using the XEN, the iStent, the KDB, the CyPass, and gonioscopy-assisted transluminal trabeculotomy (GATT), and she will be trying the Omni Combined Procedure System (Sight Sciences, Menlo Park, California). She also has experience using the InnFocus MicroShunt (Santen, Osaka, Japan) in clinical study. “The best part of the MIGS space is that the conjunctiva is preserved, so a trabeculectomy is always an option,” Dr. Moster said.

Balance of safety and efficacy

Dr. Moster thinks that MIGS procedures are a safer option compared to traditional glaucoma surgeries. “They are being extensively studied, giving us a better understanding of their limitations and side effects,” she said. “We can now pick and choose which MIGS device is best to use for which patients.”
Dr. Moster added that it’s important that the surgery balance the degree of damage. “With tubes and trabs, there are increased risks including hypotony, bleeding, suprachoroidal hemorrhage, and flat chambers,” she said. If the patient needs a lower pressure and there’s no other way to get it without these risks, they are worth taking. “But in mild to moderate glaucoma, if we can avoid these standard risks, this is certainly an advantage,” she said. “We are still doing a lot of trabs and tubes but no longer in everyone.”
“I think the XEN is a safer option, and I think visual recovery is faster,” Dr. Trubnik said, adding that she’s more likely to use it with a toric IOL. “I used to do toric with combined trabeculectomy/cataract surgeries,” she said. However, Dr. Trubnik is now more likely to use the XEN in these cases because she finds less trampolining of the anterior chamber and less likelihood of hypotony. “I think it’s a better option for patients with good central visual acuity,” she said.
Dr. Trubnik thinks the XEN is safer than a trabeculectomy, and she said that the bleb is not as ischemic. “I think that the risk of infection from bleb leak is less likely with XEN than with traditional trabeculectomy,” she said.
As far as the CyPass, Dr. Trubnik said she doesn’t have a lot of experience with it, and she has been wary about trying it because of reports of late myopic shift and hypotony. “That’s concerning to me—taking a patient with good central VA and promising a less invasive surgery,” she said. Potential for myopic shift, even if a rare complication, is concerning to her, as is the fact that there could be sudden IOP spikes with it.

Patient selection

Dr. Trubnik said that in all of her patients, even moderate and advanced cases, she’s transitioning the traditional procedures to XEN Gel Stents. She’s had multiple patients where she did a trabeculectomy before the XEN was covered by Medicare. They did well, but for the second eye, she did a XEN, and these patients did even better in terms of visual recovery.
Dr. Moster noted that in cases where there is not a lot of disease, it’s not appropriate to take a lot of risk; therefore, the iStent is something that she relies on in these mild cases.
If there’s more moderate glaucoma, she will often use a CyPass or GATT, along with cataract surgery. Meanwhile, if the goal is to lower pressure for a patient who has a thin conjunctiva or a myope, she will consider a XEN, and she hopes the InnFocus MicroShunt will be approved soon.
When asked if there’s a type of glaucoma that has remained “untouchable” by MIGS, Dr. Trubnik said that she wouldn’t use that term. “I don’t think anything is untouchable,” she said.
However, for uveitic patients, she doesn’t use options like the CyPass or iStent because she’s concerned about clogging of the stent with fibrin or white blood cells or inflammatory cells. Dr. Trubnik noted that she hasn’t used a XEN in a uveitic patient, but she would likely go straight to a tube for these patients.
She added that neovascular glaucoma is also a concern. “You don’t want hyphemas or fibrin blocking stents like the CyPass or iStent,” Dr. Trubnik said, and she thinks the same would be true for the XEN.
Dr. Moster said that she still finds trabeculectomy to be the “gold standard” to help bring a patient’s pressure down to the low teens or single digits. “There are patients who just need that,” she said. Some patients have a lot to lose if the pressure stays up, she said, and it’s not unheard of for the pressure to be uncontrolled in the immediate postop period after MIGS.
Therefore, trabeculectomies are still Dr. Moster’s go-to procedure for the “real deal” glaucoma when patients need a low pressure and have a lot to lose if it’s not obtained.

MIGS after a failed traditional glaucoma surgery

Dr. Moster said she has performed MIGS after a failed traditional glaucoma surgery, specifically using GATT.
“I’ve done GATT after failed trabeculectomies and after failed tubes, however, the trabecular meshwork needs to be visualized for 360 degrees. We can then split the trabecular meshwork in order to lower the pressure by increasing flow into Schlemm’s canal,” she said.
Dr. Moster added that MIGS procedures have broadened the field for juvenile glaucoma, especially GATT. Pressures can drop from 40–50 to 12 and stay there, she said, and this is a tremendous advantage in young people, especially contact lens wearers.
Though Dr. Trubnik has not performed MIGS after failed traditional glaucoma surgery, she said she has certainly considered it.
She has had multiple patients who had a trabeculectomy and tubes and both were not sufficient to control IOP. She’s also had patients where the tube eroded once or multiple times. Dr. Trubnik said that in these cases, she wouldn’t want to put anymore hardware on the outer surface of the eye but would consider doing a CyPass, where everything is internal, and you don’t have to worry about the shunt or any material being exposed.

Editors’ note: Dr. Moster has financial interests with Santen, Alcon, Allergan, and Glaukos. Dr. Trubnik has no financial interests related to her comments.

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