Diabetic Macular Edema Treated with 577-nm Subthreshold Micropulse Laser: A Real-Life, Long-Term Study

Abstract

The aim of this study was to evaluate the long-term efficacy and safety of 577-nm subthreshold micropulse laser (SMPL) treatment in a large population of patients affected by mild diabetic macular edema (DME) in a real-life setting. We retrospectively evaluated 134 eyes affected by previously untreated center-involving mild DME, and treated with 577-nm SMPL, using fixed parameters. Retreatment was performed at 3 months, in case of persistent retinal thickening. Optical coherence tomography (OCT), along with short and near-infrared fundus autofluorescence, were used to confirm long-term safety. At the end of at least one year follow-up, a significant improvement in visual acuity was documented, compared to baseline (77.3 ± 4.5 and 79.4 ± 4.4 ETDRS score at baseline and at final follow-up, respectively), as well as a reduction in the mean retinal thickness of the thickest ETDRS macular sector at baseline. A reduction in the central retinal thickness and the mean thickness of the nine ETDRS sectors was also found, without reaching statistical significance. No patients required intravitreal injections. No adverse effects were detected. This study suggests that 577-nm SMPL is a safe and repeatable treatment for mild DME that may be applied to real-life clinical settings using fixed parameters and protocols.

Subthreshold Micropulse Laser for Diabetic Macular Edema: A Review

“…No significant changes have been observed in fixed and variable regimens of 577 nm MPLT for mild center-involved DMEs, however, Donati et al [16] suggested that fixed parameters facilitate the treatment and reduce the number of potential errors. Frizziero et al [43] confirmed the safety of the fixed model. Nowacka et al [58] reported the stabilization of the macular structure through the maintenance of the bioelectrical function of cones and bipolar cells detected in mfERG.…”

“…The efficacy of MPLT was confirmed in various studies (Table 3) as a statistically significant improvement in or stabilization of best corrected visual acuity (BCVA) and a decrease in CRT [14,16,19,[38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54]. The first published report on 810 nm micropulsed diode laser was described in 1997 by Friberg et al [55], and it showed clinical effectiveness in the resolution of a DME.…”

Diabetes Mellitus Associated Progressive Neurovascular Retinal Injury: Recommendations for Imaging and Functional Testing and Potential Role for Early Intervention with Modern Retinal Laser Therapy

“…Several reviews and meta-analyses of MPL for DME have confirmed the superior safety and visual results vs conventional photocoagulation [181,187,[226][227][228][229][230][231][232][233]. Applying MRT principles to MPL to preclude adverse treatment effects and maximize treatment efficacy, RCTs have shown laser to be comparable if not clinically superior to intravitreal anti-VEGF therapy, with a lower treatment burden [234] and longer duration of effect [192,217,235]. (Figures 2,3 Regarding treatment of the progressive peripheral retinal as well as macular capillary non-perfusion and neuronal apoptosis, a small number of studies employing MRT principles have been reported wherein MPL is applied in a contiguous fashion over the macula and peripheral retina [188,233,237].…”

“…Within in vitro, in vivo, and in human studies, MRT RPE HSP activation results in a wide range of restorative effects that result in improved cell function, normalization of RPE cytokine expression and response normalization of retinal Mueller cell function, producing increased markers of reparative acute inflammation and decreased biomarkers of chronic inflammation, with reduced ROS, increased retinal NO, and local and systemic therapeutic immunomodulation. [152,153,193,[212][213][214][215][216][217]. Thus, by sublethal, photothermal activation of the salvific HSP response, MRT restores normalized cellular function in a manifold of ways, including via improvement in the ER UPR, without regard to the underlying clinical cause of the protein misfolding and dysfunction.…”

Intravitreal Dexamethasone Implant (IDI) Alone and Combined with Navigated 577 nm Subthreshold Micropulse Laser (SML) for Diabetic Macular Oedema

“…Diabetes mellitus (DM) is a metabolic disorder frequently complicated by diabetic retinopathy (DR) and diabetic macular oedema (DMO) [ 1 ]. The prevalence of DMO is 0–3% in newly diagnosed diabetic patients, and by 10 years, it occurs in 14 to 25% of DR patients [ 2 , 3 , 4 , 5 , 6 ]. DMO, which can occur at any stage of DR, is one of the leading causes of legal blindness in the working-age population and is the earliest and most common cause of visual loss in patients with DR [ 5 ].…”