The means to dramatically reduce glaucoma-associated morbidity are already in our hands. The problem? We don’t always use them.
by George Cioffi, MD
We already know enough to manage primary open-angle glaucoma: adequately lowering every patient’s intraocular pressure (IOP) would halt most glaucoma progression. If we just did everything possible to get every patient’s IOP to 30% below baseline or 15 mm Hg or below — whichever is less — glaucomatous vision loss would decline significantly. But we aren’t doing it, for a number of reasons.
First, glaucoma is a chronic disease, and the primary mode of therapy — topical medication—requires sustained compliance with the patient’s drug regimen. This is difficult to achieve, not because glaucoma patients are “bad,” but because human beings find compliance challenging. It’s easy to forget to take medication. When any of us is asked to take a 10-day course of antibiotics, how many pills are left in the bottle at the end of 10 days? Usually about a third of them.
A second reason that we fail to manage glaucoma adequately is that when drug therapy is no longer enough, concern for side effects makes ophthalmologists slow to move patients to the two alternative modes of therapy: laser and incisional surgery. If a drop doesn’t work or a patient develops an allergy to it, it can be discontinued, but that’s not the case with surgery. As a result, we are almost certainly pulling the trigger on laser and incisional surgery later than we should — to the detriment of patients.
Third, the payment systems for chronic disease management are inadequate. Among other issues, older patients tend to be on multiple medications, and some can’t afford all of the copays on all of their drugs every month.
Thankfully, there are ways to increase compliance, motivate doctors to perform surgery as soon as is indicated, and improve payment systems.
Getting Around Compliance
There are limits to what can be done to make patients adhere to a drug regimen, so rather than trying to fix compliance issues, the goal should be to make compliance unnecessary. Sustained-release devices — both intraocular and extraocular (eg, punctal plugs and devices worn under the lids) — are currently being investigated, and some of them may be able to deliver medication for weeks, months, or even years. At least one is in phase 3, and several are in phases 1 and 2. (Go to clinicaltrials.gov for more.)
A minimally invasive sustained-release delivery vehicle that could be refreshed or replaced once every 6 to 12 months might completely remove the burden of compliance from the patient. I am fairly confident that at least one such therapeutic device will reach the market within 3 to 5 years. I think this is the next big step forward for glaucoma therapy, although that opinion isn’t shared by everyone in the field.
In addition, a number of companies are working feverishly on small shunts that, while significantly lowering IOP, can be implanted in a minimally invasive surgical procedure. I also think this approach is within our grasp.
But even when we have good drug delivery and aqueous drainage devices, we will still need to ensure that physicians use them to keep every patient’s IOP at a safe level. And the issue of rational funding for the treatment of chronic disease will likely remain for some time.
Dr. Cioffi is the Edward S. Harkness Professor and Chairman at Columbia University, department of ophthalmology. He also holds the Jean and Richard Deems Endowed Professorship and is the Ophthalmologist-in-Chief at New York Presbyterian Hospital.