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

Efficacy of subthreshold micropulse laser photocoagulation therapy versus anti-vascular endothelial growth factor therapy for refractory macular edema secondary to non-ischemic branch retinal vein occlusion

OBJECTIVE

To assess the efficacy of subthreshold micropulse laser photocoagulation (SMLP) therapy versus anti-vascular endothelial growth factor (anti-VEGF) therapy in patients with refractory macular edema (ME) secondary to non-ischemic branch retinal vein occlusion (BRVO).

METHODS

This single-center, prospective, nonrandomized, case-control trial involved patients with refractory ME that responded poorly to three or more initial anti-VEGF injections. The patients were examined and divided into two groups according to their chosen treatment: the intravitreal ranibizumab (IVR) group and the SMLP group. Both groups were followed up monthly for 12 months. Therapeutic efficacy and safety were assessed throughout the follow-up period.

RESULTS

The IVR group comprised 49 eyes, and the SMLP group comprised 45 eyes. The improvements in the optical coherence tomography findings and visual acuity were comparable between the two groups at the final follow-up. The total number of injections was significantly lower in the SMLP than IVR group. No serious adverse events occurred during the study period.

CONCLUSIONS

SMLP therapy is better for patients with central macular thickness (CMT) of ≤400 μm. For patients with CMT of >400 μm, we advise continuation of anti-VEGF agents to reduce ME followed by application of SMLP therapy when CMT has decreased to ≤400 μm.

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.

Regional Variety of Reduction in Retinal Thickness of Diabetic Macular Edema after Anti-VEGF Treatment

Background and Objectives: The presence of refractory cases resistant to anti-vascular endothelial growth factor (VEGF) therapy for diabetic macular edema (DME) is a problem in clinical practice. This study aimed to explore the less responsive area of optical coherence tomography (OCT) 3D map the characteristics of naïve DME cases after their first anti-VEGF. Materials and Methods: In 46 patients with DME who received an intravitreal injection of anti-VEGF agents, retinal thickness in 100 sections of the macular area was measured by 3D-mapping mode using OCT before and 1 month after injection. The density of the microaneurysm (MA) was calculated using merged images of the OCT map and fluorescein angiography. Results: One month after injection, the central retinal thickness significantly decreased (p < 0.0001). In severe edema (retinal thickness more than 500 µm), the area percentages with a reduction rate of the retinal thickness greater than 30% and less than 5% were 6.4 ± 6.6% and 10.1 ± 4.6%, respectively. The reduction rate of the retinal thickness varied from section to section. The mutual distance between the areas of maximum thickness before and after the injection averaged 1.22 ± 0.62 mm apart. The reduction rate of retinal thickness in the thickest region before injection was significantly higher (p = 0.02), and that in the thickest region after injection was lower (p = 0.001) than in the other regions. MA density in the residual edema was significantly higher than in the edema-absorbed area (p = 0.03). Conclusion: DME has areas that show low response to the reduction in retinal thickness with anti-VEGF therapy. A high density of MA may be associated with this pathogenesis.

Short-term comparison between navigated subthreshold microsecond pulse laser and oral eplerenone for chronic central serous chorioretinopathy

To compare the anatomical/functional changes after navigated subthreshold pulse laser (SML) and oral eplerenone therapy for chronic central serous chorioretinopathy (cCSC). A total of 36 eyes of 36 patients suffering from cCSC treated with navigated SML (Navilas® 577s; OD-OS GmbH, near Berlin, Germany) (18 eyes, SML group) and oral eplerenone (18 eyes, eplerenone group) were enrolled in this retrospective study. Main outcome measures during a 3-month follow up period included changes of best corrected visual acuity (BCVA), central macular thickness (CMT), foveal subretinal fluid thickness (FSRFT), and subfoveal choroidal thickness (SFCT). At baseline average duration of symptoms was 6.8 ± 0.6 months in SML group and 6.4 ± 0.9 months in eplerenone group (p = 0.127). Mean BCVA, CMT and FSRFT changed significantly over time (p < 0.001). From baseline to 90 days the BCVA improved from 0.3 ± 0.1 to 0.1 ± 0.1 logMAR in SML group and from 0.3 ± 0. to 0.2 ± 0.1 logMAR in eplerenone group, CMT reduced from 357.1 ± 104.3 to 210.6 ± 46.7 μm and from 428.7 ± 107.7 to 332.5 ± 27.5 μm in SML group and eplerenone group respectively, FSRFT reduced from 144.4 ± 108.2 to 22.6 ± 37.2 μm and from 217.1 ± 105.9 to 54.4 ± 86.2 μm in SML group and eplerenone group. 55.6% of patients in SML group and 66.7% in eplerenone group showed a complete resolution of FSRFT during follow up. The interaction between group and time was statistically significant with greater absolute variation for CMT and FSRFT in SML group compared to eplerenone group (p < 0.001 and p = 0.043). SFCT did not change significantly during follow up (p = 0.083) for both groups. Both navigated SML and oral eplerenone were effective treatments showing recovery of retinal morphology and related visual acuity improvement in cCSC.

Review of clinical studies and recommendation for a therapeutic flow chart for diabetic macular edema

Diabetic macular edema (DME), characterized by exudative fluid accumulation in the macula, is the most common form of sight-threatening retinopathy in patients with diabetes. The management of DME has changed considerably in recent years, especially following the development of intravitreal anti-vascular endothelial growth factor therapy which has emerged as a first-line therapy for center-involved DME. Laser treatment, intravitreal steroid therapy, and vitrectomy are also important treatment options for DME. We believe that it is important to choose the most appropriate treatment option for DME based on the clinical evidences, in addition to the careful consideration of individual patients' general or ocular condition, DME characteristics, patients' motivation, and compliance to the treatment in real-world clinical practice. In this review, we have summarized important clinical evidences for the main treatments for DME, presented an expert review for these evidences, and proposed a recommended therapeutic flow chart for DME. We hope that our review of the clinical evidences and the recommended therapeutic flow chart for DME will contribute to better treatment outcome for DME.

Optical coherence tomography angiography assessment of 577 nm laser effect on severe non-proliferative diabetic retinopathy with diabetic macular edema

AIM

To quantitatively evaluate the effect of the combined use of 577-nm subthreshold micropulse macular laser (SML) and multi-point mode pan retinal laser photocoagulation (PRP) on severe non-proliferative diabetic retinopathy (NPDR) with central-involved diabetic macular edema (CIDME) using optical coherence tomography angiography (OCTA).

METHODS

In this observational clinical study, 86 eyes of 86 NPDR patients with CIDME who underwent SML and PRP treatment were included. Images were obtained 1d before laser and post-laser (1d, 1wk, 1, 3, and 6mo) using AngioVue software 2.0. Best corrected visual acuity (BCVA, LogMAR), foveal avascular zone area (FAZ), choriocapillary flow area (ChF), parafoveal vessel density (PVD), capillary density inside disc (CDD), peripapillary capillary density (PCD), macular ganglion cell complex thickness (mGCCT), central macular thickness (CMT), and subfoveal choroidal thickness (ChT) were compared between pre- and post-laser treatment.

RESULTS

BCVA remained stable during 6mo post-laser therapy (pre-laser vs 6mo post-laser: 0.53±0.21 vs 0.5±0.15, P>0.05). PVD, ChF, ChT, CMT, and mGCCT significantly increased 1d post-laser therapy [pre-laser vs 1d post-laser: superficial PVD (%), 40.51±3.42 vs 42.43±4.68; deep PVD (%), 42.66±3.67 vs 44.78±4.52; ChF, 1.72±0.21 vs 1.9±0.12 mm²; ChT, 302.45±69.74 vs 319.38±70.93 µm; CMT, 301.65±110.78 vs 320.86±105.62 µm; mGCCT, 105.71±10.72 vs 115.46±9.64 µm; P<0.05]. However, PVD, ChF and ChT decreased to less than baseline level at 6mo post-laser therapy (pre-laser vs 6mo post-laser: superficial PVD (%), 40.51±3.42 vs 36.32±4.19; deep PVD (%), 42.66±3.67 vs 38.76±3.74; ChF, 1.72±0.21 vs 1.62±0.09 mm²; ChT, 302.45±69.74 vs 289.61±67.55 µm; P<0.05), whereas CMT and mGCCT decreased to baseline level at 6mo post-laser therapy (CMT, 301.65±110.78 vs 297.77±90.23 µm; mGCCT, 105.71±10.72 vs 107.05±11.81 µm; P>0.05). Moreover, FAZ continuously increased while CDD and PCD continuously decreased in 6mo after laser therapy. CMT and ChT had a significant positive correlation with ChF and PVD in most post-laser stages.

CONCLUSION

During a 6-month follow-up period after combined use of SML and PRP therapy, BCVA remained stable and there was a decreased trend in macular edema. Blood flow increased at 1d post-laser therapy and reduced at 6mo post-laser therapy.

Indocyanine green angiography-guided focal navigated laser photocoagulation for diabetic macular edema

PURPOSE

To evaluate the efficacy of indocyanine-green angiography (ICGA)-guided navigated focal laser photocoagulation for diabetic macular edema (DME).

STUDY DESIGN

Prospective, interventional case series.

METHODS

Six patients (8 eyes) were enrolled in this study. Fluorescein angiography (FA) and ICGA were performed using the Heidelberg Retina Angiogram 2 (Heidelberg Engineering). Navigated focal laser photocoagulation was delivered to the microaneurysms on ICGA using Navilas^® (OD-OS GmbH, Germany). Central retinal thickness (CRT) and macular volume (MV) were measured by Cirrus HD-OCT (Carl Zeiss Meditec). At 6 months, the best-corrected visual acuity (BCVA), CRT and MV were compared to the values measured on day 0. The distances from the center of fovea to the closest microaneurysms (MAs) were measured on the pre-planned Navilas^® image.

RESULTS

All eyes had previous treatment history. At 6 months, ICGA-guided navigated focal laser photocoagulation significantly reduced the CRT and the MV (p<0.05), and there was improvement in the BCVA (p<0.05). At 3 months, 5 out of the 8 eyes (63%) underwent additional ICGA-guided navigated focal laser photocoagulation due to remnants of MAs that had been confirmed by ICGA. There was no observed recurrence of edema after the ICGA-guided navigated focal laser photocoagulation during the 6-month follow-up. The mean distance from the center of fovea to the closest MAs was 624.8 ± 377.7 μm (range 336.0-1438.9 μm).

CONCLUSION

Our data suggest ICGA-guided navigated focal laser photocoagulation may be effective for the treatment of DME.