The Rise of Interventional Glaucoma

There are roughly 3 million glaucoma sufferers in the United States and most have one thing in common. "They hate the drops," says Steven Sarkisian, MD, a glaucoma surgeon who practices in Oklahoma City, Okla. He's of course referring to the daily grind of applying — and remembering to apply — topical eye drops that lower intraocular pressure (IOP).

The number of glaucoma sufferers is expected to increase as the aging population provides a steady stream of new cases and physicians continue to recognize early stages of the disease. Patients are also becoming more aware of the following minimally invasive treatment options that can reduce the burden of a daily drop regimen. They might even show up at your facility to have them done.

• Sustained-release medications. IOP-lowering therapies can be delivered with injections, drug-eluting implants placed in the trabecular meshwork, drug-impregnated punctal plugs and conjunctival polymer rings. Some say they could supplant topical drops as the preferred non-surgical treatment method for glaucoma.

"External devices such as rings that sit in the sulcus of the eyelid or drug-eluting punctal plugs are effective, less invasive treatment options," says Jeffrey Soohoo, MD, an assistant professor of ophthalmology at the University of Colorado in Aurora.

He cautions that rings and plugs can cause discomfort in patients and are at risk of falling out, which leads to retention issues. In addition, he says, injectable sustained-release drugs such as bimatoprost SR can cause adverse ocular events and adversely impact corneal endothelial cell health.

• Minimally invasive glaucoma surgery (MIGS). Surgical options might never replace eye drops as the first-line treatment option, but MIGS is forcing surgeons and their patients to consider more aggressive interventions during earlier stages of the disease. MIGS — implantation of bypass stents in the trabecular meshwork and canaloplasty, for example — is performed to increase trabecular outflow, uveoscleral outflow and subconjunctival outflow, or decrease the production of aqueous fluid.

As surgeons continue to push for a multifaceted approach to the surgical treatment of glaucoma, fewer are performing conventional, full-thickness filtration procedures such as trabeculectomy.

"Instead of only targeting fluid outflow through the trabecular meshwork, they also attempt to reduce fluid inflow," says Dr. Soohoo.

"Individually, these procedures might not result in a home run, but together they can add up to have a significant impact on lowering intraocular pressure."

The use of non-invasive surgery and medication delivery is getting more refined, adds Richard Lewis, MD, a glaucoma surgeon at Sacramento (Calif.) Eye Consultants. "There's been a great push forward, and I think the next new wave will be an increase in drugs and devices used in combination," he says.

Dr. Sarkisian supports combining MIGS with the placement of sustained-release medication implants. "That way you have the efficacy of trabecular micro bypass with an intervention that increases uveoscleral outflow," he explains. "Combining MIGS with sustained release medications is where we're going to see the most promise in reducing intraocular pressure and getting patients off topical eye drops."

Mixed procedures are effective in reducing IOP into the mid to high teens, but more invasive treatments — trabeculectomy, for example — might still be necessary to drop the pressure to the low teens or single digits, says Dr. Lewis.

Offering patients the option of lower intraocular pressure while we're already inside the eye should be the standard of care.

— Blake Williamson, MD

"We're still striving for a medication or device that's safe, and that can lower and maintain low intraocular pressure," he says. "That would be a wonderful development."

An increasing number of surgeons combine MIGS — including placement of a trabecular micro-bypass stent, ab interno trabeculectomy and canaloplasty — to reduce IOP while implanting new intraocular IOLs.

"We're already in the eye, the incision size is the same, and the recovery and risk profiles are similar," says Dr. Soohoo.

As surgeons become more comfortable implanting stents during cataract surgery, the dual-procedure space will continue to grow, says Blake Williamson, MD, a glaucoma specialist at the Williamson Eye Center in Baton Rouge, La. He says 20% of patients who undergo cataract surgery have diagnosed glaucoma and would benefit from having MIGS performed concurrently.

It's an underserved population. "We're nowhere close to that in terms of the percentage of patients who receive glaucoma treatment during cataract surgery," says Dr. Williamson. "That needs to change."

He believes cataract surgeons should inform their patients of the benefits of combining the procedures. "Offering patients the option of lowering intraocular pressure while we're inside the eye should be the standard of care," he says.

He also points out that surgeons need to be more active and aggressive in treating glaucoma in pseudophakic patients, adding "There are more devices entering the market for that indication."

An increasing number of surgeons are implanting stents labeled for use during cataract surgery in standalone glaucoma procedures, points out Dr. Sarkisian. "Just because they were approved for use during cataract surgery doesn't mean that's the best way to use them," he says of the off-label application that's effectively reducing IOP.

Unfortunately, 5-year outcomes data for most glaucoma surgical treatments are poor — 50% of the interventions fail, according to Dr. Lewis. Experts are therefore looking for ways to improve interventional glaucoma.

"What we need, frankly, is data showing how to optimize care for individual patients with specific procedures," adds Dr. Soohoo, "but that type of data doesn't exist."

But as more surgeons adopt the mindset of interventional glaucoma specialists — treating patients with mild to moderate forms of the disease before they suffer structural or functional damage in the eye — new procedures will be developed, medications and implants will continue to evolve, and case volumes will continue to grow.

"The specialty's potential is almost unlimited," says Dr. Sarkisian. "We have the ability to capture new business and improve patient care. Surgeons just have to be willing to try new devices and techniques." OSM