BLOG: First-line glaucoma therapy: What does it take to change clinical practice?
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Laser trabeculoplasty was described in 1979 and involved an argon modality to noninvasively treat the trabecular meshwork.
The Glaucoma Laser Trial showed that initial treatment of open-angle glaucoma with argon laser trabeculoplasty was at least as efficacious as first-line medical therapy. The results of this study did not change the glaucoma treatment paradigm of initial medical therapy before consideration of laser trabeculoplasty — most likely because repeat ALT does not typically afford incremental efficacy, and patients initially treated with ALT will likely still require medical therapy during their disease course.
Selective laser trabeculoplasty was FDA approved in 2001 and may be repeated safely while offering incremental efficacy. The Laser in Glaucoma and Ocular Hypertension trial (LiGHT) randomly assigned treatment-naive and newly diagnosed patients with ocular hypertension or open-angle glaucoma to initial treatment with SLT vs. medical therapy. The trial was well conducted, and an objective target IOP was determined for all 718 patients based on disease severity. Computerized decision support software based on accepted European, Canadian and American practice guidelines then aided investigators when advancing therapies (treat-to-target design). The LiGHT investigation showed that patients initially randomly assigned to SLT were less likely to require an escalation in therapy and less likely to experience disease progression after 36 months. Importantly, 11 patients randomly assigned to initial medical therapy required trabeculectomy surgery whereas not a single subject in the SLT group required this higher-risk intervention. A high proportion of patients (74.2%) initially treated with SLT remained medication-free at 36 months. Finally, SLT was found to be safer and more cost-effective than initial medical therapy.
It is interesting to note that despite close monitoring and objective escalation criteria, a higher proportion of patients initially treated with medical therapy experienced disease progression compared with patients treated with SLT. Medication adherence issues likely partially explain this result, while nocturnal SLT efficacy may be a factor as well. Lee and colleagues performed a sleep lab study of individuals with glaucoma and demonstrated that laser trabeculoplasty consistently reduced nocturnal IOP in eyes treated medically. The ability for SLT to reduce nocturnal IOP elevations may result in lower risk for long-term visual field deterioration in patients with glaucoma. Indeed, a secondary analysis from the LiGHT investigation found that the medically treated group was more likely to experience rapid visual field progression compared with the SLT group.
In medical school, we are taught to practice evidence-based medicine and accept that clinical practice paradigms will necessarily change throughout one’s career. Recent findings with respect to the role of SLT in glaucoma management are an excellent example of this phenomenon. Practice habits are often difficult to change due to a multitude of factors, including patient attitudes. However, the evidence for first-line SLT treatment with less risk for disease progression, less risk for incisional surgery and lower cost cannot be ignored. On the basis of the current evidence, initial treatment with SLT should be recommended for patients with newly diagnosed ocular hypertension and open-angle glaucoma.
References:
- Gazard G, et al. Lancet. 2019;doi:10.1016/S0140-6736(18)32213-X.
- Lee AC, et al. Ophthalmology. 2007;doi:10.1016/j.ophtha.2006.07.058.
- Wright DM, et al. Ophthalmology. 2020;doi:10.1016/j.ophtha.2020.03.029.
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