Laser Treatment: A Better First Choice for Glaucoma?
For years, medicated eyedrops had been the mainstay for treating glaucoma, a condition caused when the pressure of fluid inside the eye becomes dangerously elevated. Then, in the mid-1990s, a new technique called selective laser trabeculoplasty (SLT) was developed to treat primary open-angle glaucoma, the most common form of the disease. A simple, in-office procedure, SLT began to be widely used as an adjunctive treatment, especially when eyedrops weren't enough to bring the pressure down to a safe level.
Now, two decades after SLT was first introduced, some experts believe that the laser procedure may be a better first-choice treatment for open-angle glaucoma, arguing that it has proven to be safe and effective and may be less expensive than medication over time for many patients.
Which treatment ophthalmologists should turn to first remains controversial, however, and ultimately the question depends not only on cost-effectiveness but also on what's appropriate for an individual patient.
There's no doubt that eyedrops are safe and effective for reducing intraocular pressure (IOP), which in turn helps prevent damage to the optic nerve. One of the most commonly prescribed classes of eyedrops, called prostaglandin analogs, increases the amount of fluid leaving the eye. Another class, called beta-blockers, decreases the amount of fluid produced inside the eye. Many patients end up using several different kinds of eyedrops to get their pressure down.
Eyedrops require nothing more than a prescription, one reason many ophthalmologists turn to them first. Glaucoma eyedrops may have some mild side effects at first, including irritation and temporary vision changes. Some may have more serious long-term side effects, including heart arrhythmias and worsening of symptoms of heart failure. But the most significant practical drawback is that people with glaucoma must apply the drops every day, sometimes several times a day, to control IOP. If patients forget, pressure inside the eye can build to dangerous levels.
Getting patients to take any kind of medication daily for a chronic condition—whether it's blood pressure pills or eyedrops for glaucoma—is challenging. Studies show that almost half of patients with chronic conditions stop using their medications within a year. Adherence to glaucoma eyedrops may be even worse. Data from pharmaceutical claims suggests that only 10 percent of patients given glaucoma medication use it as often as directed, continually, for 12 months. Perhaps that's not so surprising. Using eyedrops every day can be difficult for older patients, who are at greatest risk of developing glaucoma, an age-related condition.
Laser therapy's role
Like eyedrops, SLT has been shown in many studies to be safe and effective. During the procedure, which can be performed in an opthalmologist's office, a laser is used to destroy selected cells in a part of the eye called the trabecular meshwork.
For reasons that aren't well understood, SLT reduces intraocular pressure by increasing the flow of fluid through this meshwork and out of the eye. Reviewing findings from eight randomized-control studies in the journal Eye and Vision in 2016, researchers at the University of Antwerp found that the procedure reduced IOP by 3.8 to 8.0 mm Hg after six months to a year. The mean success rate for treatment—defined as a reduction of more than 20 percent—was between 55 and 82 percent, roughly the improvement seen with eyedrops alone.
As with any treatment, there are risks and unwanted side effects. Some patients experience temporary redness or discomfort, for example. After the procedure, SLT can cause a temporary spike in pressure within the eye, although ophthalmologists may be able to prevent those spikes by administering eyedrops. After SLT, many patients don't need eyedrops at all; others still may need drops, but less than they would have without the procedure.
The chief drawback to SLT is that the benefits typically wear off over time. In a study published in the Canadian Journal of Ophthalmology in 2011, researchers found that the success rate fell from 71 percent after the first year to 52 percent after the second year, and to 44 percent a year after that. Several recent studies have shown that the procedure can be repeated to bring the pressure back down again.
On the plus side, SLT has two important advantages over eyedrops alone: The benefits don't depend on patient adherence, and SLT appears to be less expensive over time.
At what cost?
The cost of eyedrops that must be taken every day, for years, adds up. And some brand-name drugs used for glaucoma treatment are particularly expensive in the United States. SLT can do away with the need for using eyedrops, or at least reduce the amount needed to control IOP. In a 2012 analysis published in Archives of Ophthalmology, researchers determined that SLT was less expensive than most brand-name medications one year after treatment.
Comparing the costs and benefits of eyedrops versus SLT is complicated, however, because there are so many variables to consider, from adherence and the prices of medication to how long the benefits of SLT last before the procedure needs to be repeated. Eyedrops may be the most cost-effective treatment when taken exactly as directed. But when researchers take the surprisingly high levels of nonadherence into account, SLT appears to be more cost-effective.
The bottom line
The question of whether eyedrops or SLT should be the first-line treatment for open-angle glaucoma remains controversial among ophthalmologists. But having more than one option is important, since the best choice for glaucoma treatment ultimately depends on the patient.
Eyedrops may be right for you if you're willing and able to use them exactly as directed. SLT may be a better choice if you have trouble using eyedrops, as many older or incapacitated patients do. Bear in mind that in some cases, both treatment approaches may be necessary to treat glaucoma. But reducing dependence on eyedrops can be helpful for patients who have trouble applying them.
If you've been diagnosed with primary open-angle glaucoma and are considering treatment options, the first step is to talk over your options with your ophthalmologist, so that you can make the best decision for your situation.