From the EDITOR   Over the last decade, eye care has been blessed with many new treatment options to manage glaucoma, including new medications, stents, shunts, and selective laser trabeculoplasty. Although SLT therapy has been available in the USA since the mid-90s, why has it taken so long to catch on? In this issue, my colleague, Oliver Kuhn-Wilken, provides a great explanation.

Ami Halvorson, OD

 

PCLI—Portland, OR

Selective laser trabeculoplasty (SLT) is a simple and effective treatment for open angle glaucoma. Due to a new understanding of its benefits, the popularity of this procedure has exploded in the last few years.

Optometric physicians make most of the referrals for SLT, and ODs are increasingly performing this treatment themselves. It is, therefore, crucial that we have a thorough understanding of this procedure.

Here are eight points that help explain SLT’s recent dramatic growth.

1.Interventional Glaucoma

SLT has benefitted from a significant shift in the management of glaucoma towards earlier, safer, and more aggressive treatment. This new paradigm is often referred to as “Interventional Glaucoma” and has been championed by a group of young surgeons, including Iqbal “Ike” Ahmed and Inder Paul Singh. They argue that fewer heroic surgeries are likely to be needed later if we can slow the rate of ganglion cell loss earlier.

2.The LiGHT Study

Although SLT has been around since 1995, the 2019 LiGHT study reignited interest. This carefully designed British study followed the health-related quality of life of 718 patients over 3 years following treatment with either SLT or topical medications. The researchers concluded: “We demonstrated that the treatment pathway with initial SLT is cost-effective, with no significant difference in health-related quality of life and clinical outcomes, and lower cost than the conventional treatment pathway.” They recommended that SLT be preferred as first-line treatment over eye drops and ended their report with, “Our data suggest a change in practice.” Eye doctors listened.

3.Wide Range of Candidates

SLT is approved for patients with open angle glaucoma but can also be used to treat ocular hypertension, pigment dispersion glaucoma, pseudoexfoliation glaucoma, and even steroid-induced glaucoma. The only glaucomas for which SLT is not recommended are inflammatory, iridocorneal endothelial (ICE) syndrome, uveitic, neovascular, and angle recession (traumatic).

SLT can be used as a first-line treatment in newly diagnosed glaucoma cases and in addition to glaucoma drops.

4.Effective

Many studies, including the LiGHT study, have shown that SLT is comparable to topical prostaglandin therapy, with intraocular pressure (IOP) reduction of approximately 22-30%. As with many other glaucoma treatments, the higher the pre-SLT IOP, the greater the mean response. Some have argued that SLT benefits normotensive glaucoma patients, as it may reduce intraocular pressure fluctuations. But this is controversial.

The 2019 SALT study examined whether topical steroids or NSAIDs used up to a week after SLT would influence the effectiveness of the laser treatment. The team found that 3 months after the procedure, using either of these medication classes resulted, on average, in lower IOPs. The NSAID wing, in particular, enjoyed an average additional IOP decrease of over 3 mmHg. Since this study, many doctors have been prescribing an NSAID for 4-7 days after SLT.

5.Cost Effective

The LiGHT study found that in 97% of cases, SLT lowers overall costs to glaucoma patients and the medical system.

6.Excellent Risk Profile

Complications associated with the long-term use of topical glaucoma medications are well known and include ocular surface disease, ocular and systemic reactions to the medicines, and even macular edema. SLT largely avoids these effects. Although SLT and eye drops can cause uveitis or reactivation of herpetic keratitis, this is rare. SLT’s risk profile is so favorable that one frequent justification for its use is to avoid the harmful effects of eye drops.

The 2 primary risks of SLT are that it will have little-to-no effect (thought to occur in 10-20% of patients) and that treatment will result in an IOP spike. IOP spikes are infrequent in patients with mild or moderate glaucoma (around 5%) and are treated with hypotensive drops until they subside.

7.No Fluctuation and Compliance Issues

SLT sidesteps diurnal fluctuations that often plague glaucoma patients. And, as successful treatment lowers IOP without patient effort, there are no compliance issues. Many patients appreciate being relieved of daily drop instillation.

8.Repeatable

SLT occasionally results in no IOP decrease, and even successful outcomes tend to wane after 3-5 years. But treatment can be repeated because it does not cause heating or thermal damage to the trabecular meshwork. A post hoc analysis of the LiGHT data demonstrated that a second SLT treatment was effective, and often even more so than the first. Furthermore, the effects of the second round lasted, on average, longer than the first one, leading to speculation that there might be an additive effect to SLT.

Conclusion

Although SLT has been useful for over 20 years, it owes its current renaissance to a new understanding of its worth. Our patients are benefiting.

By Oliver Kuhn-Wilken   |  PCLI—TUALATIN, OR