Laser retains limited role for management of RVO-related ME
In the current era where pharmacologic therapy is the preferred treatment for macular edema secondary to retinal vein occlusion (RVO), there is still a role for laser, according to Francesco Bandello, MD.
Reviewed by Francesco Bandello, MD
In the current era where pharmacologic therapy is the preferred treatment for macular edema secondary to retinal vein occlusion (RVO), there is still a role for laser, according to Francesco Bandello, MD.
“Laser photocoagulation–especially subthreshold laser–may be considered in eyes with a thinner macula (< 300 µm to 400 µm), and in patients for whom the use of intravitreal anti-VEGF or corticosteroid therapy is contraindicated or has failed to be effective,” said Dr. Bandello, professor and chairman, Department of Ophthalmology, University Vita-Salte, Scientific Institute San Raffaele, Milan, Italy.
“Laser may be used in combination with pharmacotherapy to stabilize the results of the intravitreal treatments,” Dr. Bandello added. “Selective laser ablation of peripheral retinal ischemia as a means to improve macular edema is topic of intense interest, but further study is needed to determine if there is a benefit for laser treatment.”
Dr. Bandello reviewed published studies investigating laser treatment for RVO-related macular edema. Information on use in eyes with central RVO (CRVO) comes from the Central Vein Occlusion Study [Ophthalmology. 1995;102(10):1425-1433] that randomized participants to macular grid laser photocoagulation or no treatment. During follow-up to 3 years, visual acuity outcomes did not differ between groups even though laser treatment significantly improved macular edema.
Outcomes of laser treatment were better in eyes were BRVO, according to results from the Branch Vein Occlusion Study [Am J Ophthalmol. 1984;98(3):271-282]. In that randomized, controlled trial, the laser-treated eyes gained an average of 1.3 lines of visual acuity, which was statistically significant compared with the untreated controls, and 65% of laser-treated eyes achieved an improvement of at least 2 lines.
“The visual function improvement with laser treatment was seen mostly in patients who were younger and who had less edema,” Dr. Bandello said.
He also noted that in a study of patients with macular branch retinal vein occlusion (BRVO), there was no significant difference in visual acuity outcome in patients randomized to early or delayed grid laser treatment compared with observation [Graefes Arch Clin Exp Ophthalmol. 1999;237(12):1024-1027].
“Macular BRVO is a specific kind of BRVO that is associated with less vision loss and usually a better prognosis,” Dr. Bandello said. “In these eyes, it is not necessary to treat with laser.”
Subthreshold technique
Subthreshold technique
Subthreshold grid laser treatment of macular edema secondary to BRVO was compared with continuous wave grid laser to see if the former procedure that is performed with a micropulse diode laser might reduce complications [Ophthalmology. 2006;113(12):2237-2242].
The results from the randomized trial showed macular edema improved rapidly with the conventional laser technique, but overall improvements in visual acuity and macular edema were similar in the two treatment groups. There were no biomicroscopic or angiographic signs of laser treatment in the subthreshold group.
Another study compared subthreshold grid laser with bevacizumab (Avastin, Genentech) in eyes with recurrent macular edema after conventional grid laser treatment [Graefes Arch Clin Exp Ophthalmol. 2015;253(10):1647-1651]. The results, both functional and anatomic, clearly favored anti-VEGF therapy in this setting, Dr. Bandello said.
Targeting the periphery
Laser treatment of peripheral ischemia is based on the idea that it would eliminate VEGF production by nonperfused retina. Various investigators have reported on this approach with conflicting results.
A small study by Rick Spaide, MD, showed panretinal photocoagulation of peripheral areas of retinal vascular nonperfusion in eyes with CRVO had no benefit for improving visual acuity or decreasing anti-VEGF injection burden [Retina. 2013;33(1):56-62].
Similar results were achieved in the RELATE trial, which randomized patients with CRVO or BRVO treated for 24 weeks with anti-VEGF therapy to continue as needed monthly injections alone or combined with scatter and grid laser photocoagulation [Ophthalmology. 2015;122(7):1426-1437]. It found the addition of laser treatment had no long-term functional or anatomic benefits, nor did it reduce anti-VEGF treatment burden, Dr. Bandello said.
In contrast, Tomomatsu et al. reported that retinal photocoagulation of non-perfused peripheral retina in eyes with ischemic BRVO prevented recurrence of macular edema after intravitreal anti-VEGF therapy [Acta Ophthalmol. 2016;94(3):e225-230].
Francesco Bandello, MD
E: Bandello.francesco@hsr.it
This article was adapted from a presentation that Dr. Bandello presented at the 2017 World Retina Congress. Dr. Bandello is an advisory board member for companies marketing products used for the treatment of macular edema secondary to RVO.
