The dropless future: SLT as a first-line treatment for glaucoma

From timolol to rho kinase inhibitors, glaucoma medications for primary open-angle glaucoma (POAG) have steadily progressed for decades.

Drop tolerance and adherence are challenges that physicians and their patients have wrestled with for years. But with advances in laser technology improving laser safety and recent research demonstrating selective laser trabeculoplasty (SLT) efficacy and safety, drops do not have to be the first line of treatment.

Now, eyecare practitioners can offer SLT with confidence as first-line therapy to control pressure and avert the challenges and unpredictability associated with glaucoma drops.

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Drops: Complaints and clinical concerns

For every familiar problem associated with glaucoma drops, there are hidden complexities. The most pronounced problem is chronic toxicity and inflammation of the ocular surface induced by medications and their preservatives. Patients can’t feel glaucoma, but they can feel dry eye symptoms.

As their eyes get red, dry, and uncomfortable, patients may stop using glaucoma drops to relieve their symptoms, and their pressure suffers.

What’s more, we know that progressive ocular surface disease (OSD) can decrease the efficacy of glaucoma surgery, such as trabeculectomy, if needed down the road.

It is also common for patients, particularly seniors, to have limited dexterity from arthritis or neck and back problems that make it difficult to position themselves for eye drop administration.

Patients with these challenges sometimes skip drops, or they require many attempts to get drops in the eye, causing them to run out of medication before insurance will pay for a refill.

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Cognitive impairment may be a barrier to adherence as well in some patients. Complex dosing regimens with different bottles and different frequencies may be confusing and lead to misuse of medications.

Cosmetic side effects-such as hyperemia, hyperpigmentation, and fat atrophy-may be discouraging in terms of adherence, particularly for younger glaucoma patients.

Many of these problems may be avoided with SLT. SLT does not require the patient to remember to dose a medication on a daily basis, and nor does it contribute to worsening OSD.

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Strong arguments have been made for cost efficacy of SLT as well. Patients may pay upward of $200 a month for a brand-name drop, whereas SLT is often well covered by insurance with a one-time, copayment for patients at the time of the procedure.

For many patients, SLT can reduce the annual financial burden of glaucoma treatment.

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SLT as first-line treatment

Since SLT was introduced by Lumenis in 2009, studies have demonstrated that it is safe, effective, and predictable. In 2019, the LiGHT study gave us the head-to-head comparison of SLT and drops that can give us the confidence to start recommending the procedure as a first-line treatment. In the LiGHT study, 718 patients were randomly assigned to SLT or medication.1

Three years later, SLT patients hit their pressure targets at more visits than those with first-line eye drop therapy. Some patients taking drops required glaucoma surgery, but none of the SLT patients did. About 74 percent of SLT patients required no drops. In addition, in 97 percent of cases, SLT was more cost-effective than eye drops as a first-line therapy.

In my treatment paradigm for POAG, I start by discussing both SLT and drops as first-line treatments.

Patients are concerned most about the safety of SLT, pain during the procedure and any restrictions on activities after treatment.

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Although most patients elect to begin with an eye drop, educating patients about SLT at the beginning of their diagnosis is helpful in introducing non-drop therapies. If patients fail to reach their target pressure with their first-line drop treatment, I strongly recommend SLT before adding another drop.

In certain cases—such as pigmentary dispersion syndrome—I strongly recommend SLT before use of drops. For younger patients, I encourage them to proceed with SLT first so as to prevent decades of medication use and the associated cosmetic and ocular surface side effects.

I also emphasize the value of SLT for patients with limited mobility or access to medications, such as people with inadequate prescription coverage and patients who are in care facilities or cannot administer drops independently.

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Patients are counseled that while there is no pain during the procedure, the treated eye may be more sensitive to light or have a low-grade ache for 2 to 3 days after.

Overall, the procedure is well tolerated, and after SLT, most patients are surprised by the ease of the procedure and minimal postoperative symptoms. People who have spent years on drops often wish they had SLT sooner.

SLT for patients with OSD

POAG patients with significant OSD may elect to proceed with SLT to reduce topical toxicity from drops. Chronic use of glaucoma medications may cause significant meibomian gland dysfunction (MGD) and OSD.

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While reducing the exposure to preservatives and caustic medications may help to reduce ocular inflammation, it may not be enough to completely alleviate all of a patient’s symptoms.

In addition to conservative measures-such as artificial tears, gels and ointments, warm compresses, eyelid scrubs and omega-3 fatty acids-additional measures may be necessary.

Dry eye medication such as lifitegrast (Xiidra, Novartis) can be helpful to reduce ocular inflammation. Intense pulsed light (IPL) treatment (Optima IPL, Lumenis) can be used to further treat the ocular surface and improve dry eye symptoms in patients. IPL helps bring the inflammatory process under control, alleviating dry eye and removing the underlying cause of MGD.

It is important to educate patients on the nature of OSD—including the inflammatory component— and to advocate for advancing therapies when conservative measures fail.

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Dropless alternatives

There are more options than ever for managing IOP, and we now have options to provide patients with treatments with a favorable side effect profile that can improve tolerance and compliance.

SLT is a tremendous tool in the treatment of glaucoma that may lead to a dropless future of glaucoma management.

Reference:

1. Gazzard G, Konstantakopoulou E, Garway-Heath D, Garg A, Vickerstaff V, Hunter R, Ambler G, Bunce C, Wormald R, Nathwani N, Barton K, et al. Selective laser trabeculoplasty versus eye drops for first-line treatment of ocular hypertension and glaucoma (LiGHT): a multicentre randomised controlled trial. Lancet. 2019 Apr 13;393(10180):1505-1516.