Medical management of glaucoma: Moving on down the road

The road to treatment of glaucoma can be circuitous to say the least, and in many cases, it is not always clear when treatment should start. Optometrists are seeing recent advances in topical therapies that entered the market following decades of reliance of traditional single-agent drops. An implantable device that facilitates the slow release of drug is changing the landscape in glaucoma therapy.

Michael Chaglasian, OD, Associate Professor at the Illinois College of Optometry and Chief of Staff of the Illinois Eye Institute, and Danica Marrelli, OD, Assistant Dean for Clinical Education and Director of Ocular Diagnostic and Medical Eye Service, both at the University of Houston College of Optometry, Houston, provide optometrists with some road signs to guide decision-making regarding initiation and choice of treatments.

The right time

The decision to start treatment requires consideration of multiple risk factors for progression and guesstimating when glaucoma might develop in a patient. The use of clinical tools, such as the OHTS Risk Calculator and imaging of the retinal nerve fiber layer, can help place patients appropriately on the risk ladder.

Chaglasian and Marrelli shared their important pearls: A decision to treat is essentially a life-long decision for patients, i.e., often up to 50 years of treatment and follow-up for patients in whom glaucoma may not develop. Glaucoma is generally a slow-moving disease and the decision to treat can be considered over time to the point at which the signs become more definitive, they emphasized.

Other considerations to be factored in is the possible long-term visual deterioration versus life expectancy, medication side effects, cost, and quality of life. “Thus, medical, laser, or surgical treatment must be delivered in conjunction with the disease severity and progression,” they said.

The right choice

Clinicians have a wide variety of single-agent drugs from which to choose, including the beta-blockers (timolol, levobunolol, betaxolol), carbonic anhydrase inhibitors (dorzolamide, brinzolamide), alpha agonists (brimondine), and the ever-popular prostaglandin analogs (latanoprost, travoprost, bimatoprost), all of which are generics.

Fixed-dose combinations are the generic dorzolamide/timolol, brimonidine/timolol (Combigan, Allergan), and brinzolamide/brimonidine (Simbrinza, Alcon).

The most recent drugs introduced for ocular hypertension and glaucoma are the rho kinase inhibitors that target the trabecular meshwork: latanoprostene bunod (Vyzulta, Bausch & Lomb), a dual-action drug also targeting the cytoskeleton; netarsudil (Rhopressa, Aerie Pharmaceuticals), and a fixed dose combination of netarsudil and latanoprost (Rocklatan, Aerie Pharmaceuticals).

All have been shown to be safe and efficacious in clinical trials.

Omidenepag isopropyl (Santen Pharmaceuticals) is a new medication that is expected to be approved by the FDA in 2022. It works by increasing aqueous drainage through both the trabecular meshwork and via uveoscleral outflow. The drug has been reported to cause fewer ocular side effects.

A big step forward in treatment is bimatoprost SR (Durysta, Allergan). This implanted device provides slow drug release over several months. The implant biodegrades over time, which varies by patient. In a clinical trial, the treatment exhibited consistent intraocular pressure (IOP) control over 15 weeks and lowered the IOP out to 2 years in some patients.

“There’s never been a better time for optometrists to get fully engaged in the diagnosis and treatment of glaucoma,” Chaglasian said. “The multitude of reliable and accurate diagnostic testing, along with a wide variety of safe and effective medications, allows for easy integration in many practice settings. Due to the aging population, there is an increasing number of glaucoma patients every year; I hope all optometrists can become more involved.”