BLOG: An update on recent micropulse laser therapy studies
While anti-VEGF injections have dramatically improved our ability to treat many retinal diseases, there is a growing pool of evidence that shows that Iridex MicroPulse laser therapy may improve anatomy, reduce the treatment burden of intravitreal injections and improve visual outcomes. Here, I summarize two studies that show the value of having this treatment in our armamentarium.
Diabetic macular edema
In a study by Mohammadreza Akhlaghi and colleagues published in Journal of Current Ophthalmology, the authors evaluated the effects of micropulse laser photocoagulation in patients with refractory diabetic macular edema. This randomized trial included 21 patients who had DME in both eyes, were resistant to treatment with intravitreal bevacizumab (IVB) and had no history of other medications, laser photocoagulation or vitrectomy. The patients also could not have had cataract surgery within the last 3 months or visually significant cataracts. One eye of each participating patient was randomly selected to receive laser therapy and IVB, while the other eye received IVB alone.
IVB injections were performed in each eye, according to standard protocols, 1 week apart. In the randomly selected eye, MicroPulse laser photocoagulation was also performed with either the 810 nm laser or the Iridex IQ 532 in a multifocal grid pattern in the region of the edema. Patients were examined at 1 month, and the IVB injections were repeated at 1 month and 2 months in both eyes.
One month after the third injection, logMAR best corrected visual acuity and central macular thickness (CMT) were assessed. The results were as follows:
• BCVA with laser and IVB was 0.81 ± 0.33 at baseline, 0.74 ± 0.28 at 1 month and 0.62 ± 0.26 at month 3 (P < .001).
• BCVA with IVB alone was 0.70 ± 0.33 at baseline, 0.75 ± 0.33 at 1 month and 0.79 ± 0.33 at month 3 (P = .01).
• CMT with laser and IVB was 513 ± 126.29 µm at baseline, 454.62 ± 94.79 µm at 1 month and 408.1 ± 95.28 µm at month 3 (P < .001).
• CMT with IVB alone was 494.38 ± 130.7 µm at baseline, 492.14 ± 130.27 µm at 1 month and 502.38 ± 145.88 µm at month 3 (P = .064).
In this study, IVB alone did not show a significant improvement in BCVA or CMT, whereas IVB plus MicroPulse laser therapy showed improvement in both areas. It is known that the pathophysiology of DME is multifactorial and includes both an increase in vascular endothelial growth factor as well as other vitreous inflammatory factors. Treatment by multiple modalities appears to offer potential for better results.
Macular edema secondary to BRVO/CME
In a study by Hiroko Terashima and colleagues published in Retina, the authors looked at the efficacy of combining 577 nm MicroPulse laser photocoagulation (MLP) with intravitreal ranibizumab (IVR) for the treatment of macular edema secondary to branch retinal vein occlusion cystoid macular edema. This retrospective, consecutive, case control study included 46 eyes of 46 patients who were treatment-naive. A combination therapy of IVR plus MLP was performed in 22 eyes, and IVR monotherapy was performed in an additional 24 eyes. All patients received an initial injection of IVR, and additional IVR was delivered pro re nata in cases of new or persistent cystoid retinal changes and serous retinal detachment, an increase of central retinal thickness (CRT) greater than 20%, or a worsening of BCVA by more than 0.2 logMAR. The combination group was treated with MLP 1 month after IVR, and additional laser treatments were performed at intervals of at least 3 months if there was a recurrence at that time.
The number of IVR injections in the combination therapy group was 1.9 ± 0.8 compared with 2.3 ± 0.9 in the IVR group. MLP was performed an average of 1.4 times over 6 months in the combination group.
While both treatments showed a similar immediate effect after IVR, the patients who had combined therapy demonstrated more durability in both visual acuity and anatomic improvement. In addition, no serious ocular or non-ocular complications associated with IVR or MLP were observed in any of the eyes over the entire observation period (6 months after treatment). Also, no laser spots were detected in any treated areas on swept-source OCT, color fundus photography or fluorescein angiographies.
Akhlaghi M, et al. J Curr Ophthalmol. 2018;doi:10.1016/j.joco.2018.11.006.
Terashima H, et al. Retina. 2019;doi:10.1097/IAE.0000000000002165.
Disclosure: Luo reports he is a consultant for AbbVie, Alimera, Allergan, Genentech, Iridex and Lumenis and receives research grants from Allergan and Lumenis.