December 2015

 

GLAUCOMA

 

Ten patient types who can benefit from SLT


by Nathan Radcliffe, MD

 
   
Old man

SLT may be beneficial in patients who are having problems with eye drops or who have insurance issues, according to Dr. Radcliffe.

Physician explains why the pool of potential patients for SLT may be wider than you think

Over the past year, many of my patients have benefited from selective laser trabeculoplasty (SLT). In observing these outcomes, I have come to realize that although SLT is beneficial for a wide range of patients, there are differing reasons why it is a successful strategy. In this article, I will discuss the 10 patient types I think benefit from SLT therapy. Of note, these are not necessarily presented in rank order, as each patient type will benefit from SLT, albeit for different reasons.

#1: SLT as a replacement for drop therapy

As I look at successes that I have had with SLT over the past several years, it is clear to me that SLT is more successful the earlier you use it in the treatment paradigm. Indeed, this is true of most therapies. Consider the patient who really needs a trabeculectomy or a tube shunt to help control his or her pressure, but who is resistant to undergo an invasive incisional glaucoma procedure. These are the kinds of patients who exhibit poor control on four or five topical agents, and nothing seems to work. While I will use SLT in these kinds of patients, I adjust my expectations for outcomes. When the pressure is 40 mm Hg, a 35% pressure reduction may not be sufficient, and we are setting ourselvesand the SLT procedureup for failure if we expect a miracle outcome. This is something I tell surgeons learning the ins-and-outs of SLT: Do not start with the impossible cases; set yourself up for success.

Contrast the above scenario to simply using SLT as a replacement for eye drops in patients who are having problems with eye drops but who have controlled intraocular pressures. For example, consider a 75-year-old man who has exam findings that place him somewhere between being a high risk glaucoma suspect and having early primary open-angle glaucoma. Even with minimal symptoms from eye drops, the quality of life downsides of paying for and remembering to use topical medications likely outweigh any benefits of pressure-lowering therapy because his overall risk of visual impairment is so low. In this case, shouldnt the treatment be low impact as well? SLT would more likely than not successfully replace the pressure lowering of a prostaglandin analog and restore the patients quality of life.

#2: SLT as primary therapy

SLT is commonly used as a replacement for previous therapy that has failed for reasons of inadequate efficacy or because the patient had a complication. As shown by Waisbourd and Katz, however, SLT is also an excellent option for first-line therapy of glaucoma, offering several advantages including convenience, compliance and tolerability, in addition to efficacy that is similar to eye drops.1

#3 + 4: Previously successful SLT and previously unsuccessful SLT

One of the benefits of SLT is that it is a repeatable procedure. It has largely replaced argon laser trabeculoplasty (ALT), which promises roughly equivalent efficacy, but which is ablative to the trabecular meshwork and is therefore not repeatable. However, SLT is highly successful as a repeat procedure. Patients who respond to a first procedure can expect a similar response with a secondary procedure.2,3 However, the outcome of previous SLT does not necessarily predict if a secondary procedure will work. Khouri and colleagues showed that a repeat SLT procedure will be effective even in patients who did not demonstrate a great response to initial SLT therapy.4 Therefore, repeat SLT can be offered to both the previous SLT responders and to previous SLT non-responders. Note that this is not typically the case with people who have not previously responded to a given class of medications.

#5: Adjunctive therapy as an alternate to more drops

Tanna performed a meta-analysis on adjunctive pressure lowering with a variety of glaucoma medications and found that an additional 2 to 3 mm Hg drop in pressure is added with a second drop, almost irrespective of the class of agent used (there is some variance, but overall, there is a very minimal difference). However, whereas adding a second agent will lower pressure, it also has the effect of reducing overall compliance. In many patients, adding a second drop is a zero-sum gain. This is the ideal scenario to try SLT: The potential for a very minimal decrease in pressure with an adjunctive agent may not be worth it if there is an increased chance of decreased complianceespecially when that adjunctive agent adds an entirely new category of risk associated with side effects and/or ocular surface intolerability.

Lee and colleagues demonstrated that when SLT was added to medications, there was further reduction in IOP and medication use without significant decreases in quality of life or worsening of medication tolerability.5

#6: Trouble with compliance

Closely related to the previous category is when there is concern for a patients compliance with primary therapy. I have developed a zero tolerance policy for patients who miss drops because there are viable alternate options, and SLT tops the list. Studies suggest that about 40% of patients miss an eye drop instillation (or use it incorrectly) in the week leading up to appointment. We can help these patients achieve their target pressure with laser. When a patient takes drops, the SLT and drops are equivalent in terms of efficacy, but when the patient does not take drops, there is no question the laser is a better choice.

#7: Patients with insurance issues

A few months ago, I had a patient in my clinic tell me that his new insurance company would not cover the brand-name prostaglandin analog I had prescribed him. After some consultation, we moved forward with laser to replace the therapy no longer covered by his insurance company. It turned out that this patient was struggling with high copays even prior to the change in coverage, so he was very happy to be rid of copays and have a therapy that was working without him having to go to the pharmacy. I would venture to guess this is not an uncommon scenario for many patients being treated for glaucoma. Many patients enrolled in Medicare do not have a prescription drug plan, so SLT is a very relevant option for them. As I have found myself discussing copays with patients more over the past year, I have often been startled by how much some have to pay for pharmacotherapy. I have made it a priority to, when appropriate, replace my patients copays by using laser. I have found this to be most effective among patients on a single medication.

It is not surprising that patients might want to have SLT rather than pay for eye drops, as SLT has been shown to be cost effective in comparison to drops. In fact, SLT is less costly than generic latanoprost for 13 months. If the SLT lasts beyond 13 months, as most do, or if the medication is more expensive than generic latanoprost, as most are, then SLT is more cost effective.6 More importantly, however, studies demonstrate that SLT can be as effective as topical therapy in reducing pressure, so the added cost may not be justifiable.7

#8: MIGS patients

I have been very pleased with the results I get when I perform a MIGS procedure at the time of cataract surgery, but I have also found that the results cannot be counted on 100% of the time. I have seen patients achieve excellent visual outcomes, but the pressure is the same on a similar number of medications after the cataract surgery. In these patients, I usually observe for 6 months to be sure that residual inflammation or steroid responses are not a factor. After that 6-month waiting period, if the pressure is still the same, then it is time to figure out a new planand SLT is an excellent option. Indeed, SLT can provide further IOP lowering even after cataract and MIGS surgeries that are performed on the angle, such as Trabectome (NeoMedix, Tustin, Calif.) and deep sclerectomy.8,9

#9: Steroid responders

There are many patients who may not have glaucoma but are, for one reason or another, on a topical or intravitreal steroidfor example, patients with diabetic macular edema who receive a slow-release corticosteroid implant or who have multiple intravitreal triamcinolone injections. In these patients, steroid response can be an issue. Although topical therapy is often used, SLT is an equally good choice, and it is one that avoids the potential for ocular surface intolerance or compliance issues.

#10: Patients with narrow angles who undergo unsuccessful laser iridotomy

Many people think SLT is not an option for this patient type because they are thought of in the category of angle-closure. However, if the angle remains open, as visible on gonioscopy, and if the pathology is at the level of the trabecular meshwork (which it is), then why should such patients be disqualified from SLT? Aung and colleagues randomized almost 200 patients with chronic angle-closure glaucoma after iridotomy to prostaglandin therapy or SLT and found a similar IOP reduction between the two therapies.10

References

1. Waisbourd M, et al. Selective laser trabeculoplasty as a first-line therapy: a review. Can J Ophthalmol. 2014 Dec;49(6):51922. 2. Avery N, et al. Repeatability of primary selective laser trabeculoplasty in patients with primary open-angle glaucoma. Int Ophthalmol. 2013 Oct;33(5):5016.

3. Hong BK, et al. Repeat selective laser trabeculoplasty. J Glaucoma. 2009 Mar;18(3):1803. 4. Khouri AS, et al. Repeat selective laser trabeculoplasty can be effective in eyes with initial modest response. Middle East Afr J Ophthalmol. 2014 JulSep;21(3):2059. 5. Lee JW, et al. A randomized control trial to evaluate the effect of adjuvant selective laser trabeculoplasty versus medication alone in primary open-angle glaucoma: preliminary results. Clin Ophthalmol. 2014 Sep 5;8:198792.

6. Seider MI, et al. Cost of selective laser trabeculoplasty vs topical medications for glaucoma. Arch Ophthalmol. 2012 Apr;130(4):52930.

7. Katz LJ, et al. Selective laser trabeculoplasty versus medical therapy as initial treatment of glaucoma: a prospective, randomized trial. J Glaucoma. 2012 Sep;21(7):4608.

8. Klamann MK, et al. Influence of selective laser trabeculoplasty (SLT) on combined clear cornea phacoemulsification and Trabectome outcomes. Graefes Arch Clin Exp Ophthalmol. 2014 Apr;252(4):62731.

9. Baykara M, et al. Early results of selective laser trabeculoplasty in patients resistant to deep sclerectomy. Eur J Ophthalmol. 2014 MayJun;24(3):3714. 10. Narayanaswamy A, et al. Efficacy of selective laser trabeculoplasty in primary angle-closure glaucoma: a randomized clinical trial. JAMA Ophthalmol. 2015 Feb;133(2):20612.

Editors note: Dr. Radcliffe is director of the glaucoma service, New York University Langone Medical Center, New York. He has no financial interests related to this article.

Contact information

Radcliffe
: drradcliffe@gmail.com

10 patient types who can benefit from SLT 10 patient types who can benefit from SLT
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