Macular laser photocoagulation in the management of diabetic macular edema: Still relevant in 2020?

Effect of ranibizumab combined with laser photocoagulation in the treatment of diabetic macular edema

Objective

To explore the clinical effect of ranibizumab combined with laser photocoagulation (LP) in treating diabetic macular edema (DME).

Methods

We retrospectively reviewed the clinical data of 118 patients with DME admitted to The Affiliated Eye Hospital of Nanchang University from May 2021 to March 2023. Among them, 38 patients received LP alone (Laser-group), 39 patients received ranibizumab alone (Ranibizumab-group), and 41 patients received LP combined with ranibizumab (Combined-group). The improvement of macular edema (ME), visual acuity, and complications between the groups were compared.

Results

The time of ME regression, exudation absorption and fundus hemorrhage absorption in the Combined-group was shorter than in the Laser-group and the Ranibizumab-group (P<0.05). After treatment, the CMT and RNV of the three groups decreased compared to pretreatment levels and were lower in the Combined-group compared to the Laser-group and the Ranibizumab-group (P<0.05). BCVA increased after the treatment in all groups, and was markedly higher in the Combined-group than in the Laser and the Ranibizumab-groups (P<0.05). NO were higher in the Combined-group compared to the Laser-group and the Ranibizumab-group. The post-treatment VEGF levels decreased in all groups, and were significantly lower in the Combined-group compared to the Laser-group and the Ranibizumab-group (P<0.05). The incidence of complications in the Combined-group was lower than in the Laser-group and the Ranibizumab-group (P<0.05).

Conclusions

Compared to ranibizumab or LP alone, ranibizumab combined with LP is more effective in reducing ME in patients with DEM, and is associated with fewer complications.

Subthreshold Micropulse Laser for Diabetic Macular Edema: A Review

Diabetic macular edema (DME) is one of the main causes of visual impairment in patients of working age. DME occurs in 4% of patients at all stages of diabetic retinopathy. Using a subthreshold micropulse laser is an alternative or adjuvant treatment of DME. Micropulse technology demonstrates a high safety profile by selectively targeting the retinal pigment epithelium. There are no standardized protocols for micropulse treatment, however, a 577 nm laser application over the entire macula using a 200 μm retinal spot, 200 ms pulse duration, 400 mW power, and 5% duty cycle is a cost-effective, noninvasive, and safe therapy in mild and moderate macular edemas with retinal thickness below 400 μm. Micropulse lasers, as an addition to the current gold-standard treatment for DME, i.e., anti-vascular endothelial growth factor (anti-VEGF), stabilize the anatomic and functional retinal parameters 3 months after the procedure and reduce the number of required injections per year. This paper discusses the published literature on the safety and application of subthreshold micropulse lasers in DME and compares them with intravitreal anti-VEGF or steroid therapies and conventional grid laser photocoagulation. Only English peer-reviewed articles reporting research within the years 2010-2022 were included.

Comparison of two-year treatment outcomes between subthreshold micropulse (577 nm) laser and aflibercept for diabetic macular edema

PURPOSE

To compare two-year treatment outcomes of subthreshold micropulse (577 nm) laser and aflibercept for diabetic macular edema (DME).

STUDY DESIGN

Retrospective case-control study.

METHODS

A total 164 eyes in 164 DME patients treated with either micropulse laser (86 eyes) or intravitreal aflibercept monotherapy (78 eyes) were recruited. Main outcome measures included at least five Early Treatment Diabetic Retinopathy Study (ETDRS) letters' improvement from baseline at 6, 12 and 24 months.

RESULTS

Rescue aflibercept was initiated in 24% of eyes in micropulse laser group. At 6-month visit the aflibercept group achieved a higher percentage of eyes with at least 5-letter visual acuity improvement than micropulse laser group (56% vs 38%, P = 0.044), however, this was not the case at 12-month (45% vs 49%, P = 0.584) and 24-month visits (49% vs 57%, P = 0.227). At 6-month visit the aflibercept group achieved a higher percentage of eyes with at least 10% improvement of central macular thickness (73% vs 49%, P = 0.005), but this was not the case at 12-month (73% vs 70%, P = 0.995) and 24-month visits (85% vs 84%, P = 0.872).

CONCLUSION

Aflibercept achieved faster and higher rates of anatomical and functional improvement than micropulse laser in DME patients. Long term efficacy of treatment did not result in significant differences between aflibercept monotherapy and micropulse laser in DME patients. Primary treatment of micropulse laser with deferred rescue aflibercept might be the treatment option without reducing the chance of visual improvement in DME eyes.