Subthreshold Micropulse Laser Modulates Retinal Neuroinflammatory Biomarkers in Diabetic Macular Edema

Abstract

Subthreshold micropulse laser treatment has become a recognized option in the therapeutic approach to diabetic macular edema. However, some yet undefined elements pertaining to its mechanism of action and most effective treatment method still limit its clinical diffusion. We reviewed the current literature on subthreshold micropulse laser treatment, particularly focusing on its effects on the modulation of retinal neuroinflammation. Subthreshold micropulse laser treatment seems to determine a long-term normalization of specific retinal neuroinflammatory metabolic pathways, contributing to the restoration of retinal homeostasis and the curtailing of local inflammatory processes. Optimized and standardized parameters ensure effective and safe treatment.

Efficacy and Safety of Subthreshold Micropulse Yellow Laser for Persistent Diabetic Macular Edema After Vitrectomy: A Pilot Study

“…In our study no modifications on autofluorescence or on FFA have been detected, supporting its safety even when used on the macular area ( Gawecki, 2019 ; Midena et al, 2021 ). These results confirm that SMYL therapy acts on the outer blood–retinal barrier and on the pigmented epithelium (RPE) ( Gawecki 2019 ; Frizziero et al, 2021 ; Midena et al, 2021 ). RPE layer is considered to be the main site of action of SMYL.…”

“…Subthreshold micropulse yellow laser (SMYL) is a new treatment option that turns out to be safe and effective in the treatment of macular edema induced by different retinal diseases, including DME in naïve eyes. SMYL uses a photo-stimulation process with repetitive short pulses at low temperatures through which the tissue is preserved ( Frizziero et al, 2021 ). Yellow light has an excellent absorption rate for O2 Hb and is not absorbed by foveal pigments such as lutein and zeaxanthin, thus allowing central macular edema treatment without foveal damage ( Gawecki 2019 ).…”

Real World Data Comparison of Standard Care vs SDM Laser Vision Protection Therapy for Prevention of Neovascular AMD

“…A few include normalization of RPE cytokine expression/balance including decreased VEGF and increased pigment epithelial derived factor levels; normalized antioxidant balance and tissue nitrous oxide levels; decreased markers of disease-driving chronic inflammation; improved mitochondrial function, anti-apoptosis, increased markers of reparative acute inflammation, and restorative local and systemic immune response modulation. 6 , 7 , 11 , 34–41 Such effects, maintained by regular periodic treatment, may account for our findings. 7 , 8 While intravitreal anti-VEGF drugs have improved the management and visual prognosis of wet AMD, conversion to neovascular or “wet” AMD from dry AMD continues to be the main cause of age-related visual loss, decreased quality of life, loss of independence in older adults, and a tremendous economic and social healthcare burden worldwide.…”

“… 14 SDM, by contrast, is homeotrophic (functionally restorative) to the RPE, is anti-inflammatory, improves retinal function, and is anti-neoangiogenic, thus improving the ability of the retina to resist choroidal neovascularization. 5–24 , 34–41 A prerequisite for slowing disease progression and reducing adverse events such as visual loss in chronic progressive disease, such as neovascular conversion and vision loss in AMD, is prompt, and then maintained, improvement in retinal function. 5 , 6 , 11 This is the basis of the VPT strategy, and, for that matter, any effective preventive treatment.…”

State-of-the-Art Research on Diabetic Retinopathy

“…Since fenofibrate could be a potential drug for treating DR, this intriguing finding deserves further research. Frizziereo et al [11] review subthreshold micropulse laser treatment as a therapeutic approach to diabetic macular edema and conclude that this laser modality seems to determine a long-term normalization of specific retinal neuroinflammation. Therefore, it is possible that those patients with more glial activation/inflammation, which might be identified by means of a liquid biopsy of aqueous humor, could be the most appropriate candidates for this laser modality.…”