For a long time, ophthalmologists had sort of given up on recovering the drainage functions of the trabecular meshwork of a glaucoma patient’s eye.
Ophthalmologist Anita Campbell, MD, is a fellowship-trained glaucoma specialist at Grene Vision Group. She provides the latest medical care and surgical techniques, including minimally invasive glaucoma surgery.
In the pas 18 months, the FDA has approved two new glaucoma eyedrop medications and certified two types of minimally invasive glaucoma surgeries (MIGS) to restore some functionality of the meshwork, says Anita Campbell, MD, a fellowship-trained glaucoma specialist at Grene Vision Group in Wichita.
Dr. Campbell has started prescribing both new medications — Vyzulta and Rhopressa — and performing both new MIGS procedures — called the Kahook Dual Blade and the OMNI system — to help reduce intraocular pressure (IOP) in the eyes of her glaucoma patients.
Dr. Campbell uses a kitchen sink analogy to explain the eye’s fluid dynamics to patients: The faucet is the ciliary body that produces fluid or aqueous humor, and the drain is the trabecular meshwork. In the most common form of glaucoma, called open angle, the meshwork gets blocked, leading to buildup of the aqueous humor. The fluid buildup leads to elevated pressure on the optic nerve. If left untreated, the elevated IOP can cause optic nerve damage and permanent blindness.
Treatment for glaucoma patients involves medications or surgeries that either turn down aqueous humor production or increase aqueous fluid drainage through traditional or secondary pathways, Dr. Campbell says.
How the New Meds Work
“What makes these new medications so exciting is that they salvage the primary drain, and we’d given up on that medicine-wise,” Dr. Campbell says. “If there are new medications that can hold off on a patient needing surgery, that’s good.”
Vyzulta, manufactured by Bausch + Lomb, was approved by the FDA in November 2017. A month later, the FDA approved Rhopressa, which was developed by an ophthalmologist and is made by Aerie Pharmaceuticals.
There are six categories of glaucoma eyedrops, and these tend to be the first-line treatment for glaucoma patients. Some work by decreasing fluid production and others create a secondary drainage channel via the uveoscleral outflow, and some do both. The uveoscleral outflow allows the fluid to seep around the trabecular meshwork. In the sink analogy, the uveoscleral outflow is the equivalent of making a crack in the sink next to the drain and letting the fluid fall into the cupboards below.
In the prostaglandin category, Vyzulta helps increase drainage via the uveoscleral outflow, but because its formulation includes nitric oxide, it additionally relaxes vascular smooth muscle to open up the meshwork. This dual-action mechanism makes Vyzulta a good initial glaucoma treatment, Dr. Campbell says.
Rhopressa falls in the rho-associated protein kinase inhibitor category. The rho kinase enzyme is activated downstream from nitric oxide’s cellular messaging. By inhibiting production of the rho kinase enzyme, Rhopressa helps relax the muscles in the meshwork to allow for more drainage. Dr. Campbell prescribed the medication for about 60 eyes by Jan. 1, and it has reliably lowered pressure in those eyes, she says. One patient’s pressure reading went from 18 to 7, she says, saving the patient from surgery. Rhopressa is an effective adjuvant glaucoma therapy, Dr. Campbell says.
Like any medication, the new eyedrops can have some side effects. Vyzulta’s side effects can include eyelash growth, which is common with the prostaglandins, and a color change in the patient’s iris. The latter has been a risk that some patients aren’t willing to take, Dr. Campbell says. Rhopressa’s side effects can include eye redness or conjuctival hemorrhage, which lessen over time.
New Surgical Options
For patients who need surgical intervention, the options for MIGS are growing.
“The older surgeries that we call traditional surgeries were invasive and involved making larger incisions that took months to heal,” Dr. Campbell says. “With the minimally invasive surgeries, the incisions are extremely small and heal within a week.”
Because of advancing technologies, several MIGS procedures have become available in recent years. The two latest options, joining four other MIGS on Dr. Campbell’s surgical list, are the Kahook Dual Blade and the OMNI. Both help salvage the drainage functions of the trabecular meshwork, unlike the other options that either decrease fluid production or provide alternate drainage channels.
The Kahook procedure removes a section of the meshwork tissue, so the fluids flow directly to the Schlemm’s canal. The OMNI also removes part of the meshwork to allow direct drainage, but it also injects viscoelastic fluid farther downstream to clear out the pipes and improve eye pressure.
For more information about glaucoma treatment options or to make a referral, contact Grene Vision Group, 316-684-5158 or visit grenevisiongroup.com.