The Role of Laser Photocoagulation in Treating Diabetic Macular Edema in the Era of Intravitreal Drug Administration: A Descriptive Review.

Background and Objectives: This study aimed to elucidate the role of laser photocoagulation therapy in the treatment of diabetic macular edema (DME) as an alternative to, or in conjunction with, the first-line treatment, anti-vascular endothelial growth factor (VEGF). Materials and Methods: A comprehensive literature search to identify studies that evaluated the efficacy of laser photocoagulation therapy in the management of DME was performed. The relevant findings of the efficacy of focal/grid laser therapy from data in randomized, controlled trials were synthesized, and the potential of new laser technologies, such as navigated laser systems, pattern scan lasers, and subthreshold lasers, was explored. The usefulness of multimodal imaging-guided laser therapy was also evaluated, with a focus on the potential contribution to anti-VEGF therapy. Results: Focal laser photocoagulation targeting microaneurysms remains an effective therapeutic approach to chronic refractory edema, despite the widespread use of anti-VEGF therapy. To achieve the best possible treatment outcomes, precise identification of microaneurysms is essential. This requires the use of multimodal imaging-guided, highly accurate, minimally invasive coagulation techniques. Subthreshold laser therapy can also reduce the frequency of anti-VEGF injections and minimize treatment burden. Conclusions: Further studies are needed to determine the optimal timing and settings for laser photocoagulation therapy and the potential of new laser technologies in the management of DME. Nevertheless, laser photocoagulation therapy plays an important role in the management of DME, in conjunction with anti-VEGF therapy.

Retinal Microvascular Changes after Intravitreal Triamcinolone Acetonide in Diabetic Macular Edema.

Intravitreal injection of triamcinolone acetonide (TA) is essential for clinical treatment in patients who insufficiently respond to vascular endothelial factor inhibitors for diabetic macular edema (DME). The aim of this study was to investigate microvascular changes treated with TA using optical coherence tomography angiography (OCTA). After TA in twelve eyes of eleven patients with central retinal thickness (CRT), there was a 20% or more reduction observed. Visual acuity, the number of microaneurysms, vessel density, and the foveal avascular zone (FAZ) area were compared before and at 2 months after TA. At baseline, the number of microaneurysms was 2.1 ± 1.1 in the superficial capillary plexuses (SCP) and 2.0 ± 1.1 in the deep capillary plexuses (DCP), with a significant decrease post-treatment to 1.0 ± 1.0 for SCP and 0.8 ± 0.8 for DCP (SCP; p = 0.018, DCP; p = 0.008). There was significant enlargement of the FAZ area from 0.28 ± 0.11 mm2 to 0.32 ± 0.14 mm2 (p = 0.041). There was no significant difference in the visual acuity and vessel density of SCP and DCP. Results indicated that OCTA was useful for the evaluation of qualitative and morphological retinal microcirculation and that intravitreal TA may decrease microaneurysms.

Evaluation of Navigated Laser Photocoagulation (Navilas 577+) for the Treatment of Refractory Diabetic Macular Edema.

PURPOSE: To evaluate navigated laser photocoagulation for the treatment of refractory diabetic macular edema (DME). METHODS: Retrospective study of 25 eyes (21 patients) treated with Navilas 577+ focal laser system. Best-corrected visual acuity (BCVA) and spectral-domain optical coherence tomography (OCT) parameters were measured at baseline, 1, 3, and 6 months, and final visit. RESULTS: The mean follow-up period was 12.8 ± 2.4 (7-16 months). All subjects had history of previous treatment which was injection of triamcinolone acetonide or antivascular endothelial growth factor (VEGF) agents. The navigated laser photocoagulation was delivered to the microaneurysms on indocyanine green angiography (ICGA) in 21 of 25 eyes (84%), fluorescein angiography (FA) guided in 3 eyes, and OCT angiography guided in 1 eye. After initial navigated laser treatment, 16 of 25 eyes (64%) were needed additional navigated laser photocoagulation, injection of triamcinolone acetonide, and/or injection of VEGF agents. Although median BCVA remained stable, the central retinal thickness and macular volume were significantly decreased over 6 months (p < 0.05). All patients were treated without complications. CONCLUSIONS: Focal photocoagulation using Navilas 577+ showed to be effective in treating DME with improvement in macular edema on OCT over 6 months. Navilas 577+ was beneficial to perform navigated laser photocoagulation based on three modalities (ICGA, FA, and OCT angiography).

Correlation between N2 amplitude of multifocal ERGs and retinal sensitivity and retinal nerve fiber layer thickness in glaucomatous eyes.

PURPOSE: To determine whether there are significant correlations between the N2 amplitude of the multifocal electroretinograms (mfERGs) and the retinal sensitivity and retinal nerve fiber layer (RNFL) thickness in glaucomatous and normal eyes. METHODS: Thirty-eight glaucomatous and 11 normal eyes were studied. The mfERGs were elicited by red stimuli presented on a blue background. The responses from the central five elements within a 20° stimulated area were analyzed. The retinal sensitivity was determined by Humphrey Field Analyzer and the RNFL thickness by spectral-domain optical coherence tomography. The correlations between the N2 amplitude and the retinal sensitivity and the RNFL thickness were calculated. RESULTS: The N2 amplitude was significantly smaller in the glaucomatous eyes than the normal eyes in all areas (P < 0.05). There was a significant correlation between the N2 amplitude and the retinal sensitivity (1/Lambert linear unit) of the HFA for the superior retina (r = 0.36, P = 0.01), for the central retina (r = 0.54, P < 0.0001), and for the inferior retina (r = 0.51, P = 0.0001). There were significant correlations between the N2 amplitude and the RNFL thicknesses in the superior retina (r = 0.49, P = 0.0003), the central retina (r = 0.79, P < 0.0001), and the inferior retina (r = 0.52, P = 0.0001) for both normal and glaucomatous eyes. CONCLUSIONS: These results indicate that the activity of the retinal ganglion cells contribute to the amplitude of the N2 of the mfERGs and thus can be used as an objective monitor of retinal ganglion cell function.