Title

REAL-LIFE OUTCOMES OF SUBLIMINAL LASER PHOTOSTIMULATION FOR DIABETIC MACULAR EDEMA

Introduction

Diabetic macular edema (DME) is a major cause of visual impairment and its treatment is a public health challenge. Even though anti-angiogenic drugs are the gold-standard treatment, Subliminal® laser photostimulation (SLP) is looking promising in selected cases. The aim of this study was to evaluate its efficacy in a real-life setting

Methods

Retrospective case series of 56 eyes of 36 patients with center-involving DME treated with SLP monotherapy. Treatment was performed in a single session with the EasyRet® photocoagulator (Quantel Medical, France) and the following parameters: 5% duty cycle, 200ms pulse duration, 160µm spot size and 50% power of the barely visible threshold. A high-density pattern was then applied to the whole edematous area, using Multispot mode. BCVA and OCT data were obtained at baseline and after 3 months

Results

Among 79 eyes treated, 56 were included in the analysis. 39% of patients were women, and the mean time between treatment day and follow-up visit was 14 ± 6 weeks. BCVA (logMAR) was 0.59 ± 0.32 and 0.43 ± 0.25 at baseline and follow-up, respectively (p = 0.002). 43% of eyes exhibited a >10% central macular thickness reduction post-treatment. Intraretinal (IRF) and subretinal fluid (SRF) was seen in 96 and 41% of eyes at baseline and improved in 35 and 74% of those after treatment, respectively. 32% had prior panretinal photocoagulation, showing correlation with VA improvement (p = 0.011). Mean laser power was 555 ± 150 mW and number of spots was 1,109 ± 580

Discussion

Subthreshold laser therapy is known to have RPE modulation as its main target mechanism, activating heat-shock proteins and normalizing cytokine expression. In the present work, the DME cases associated with SRF had the best anatomical response, while IRF responded poorly to laser monotherapy. BCVA and macular thickness exhibited a mild response, suggesting the need for combined treatment in most patients. Given the effect on SRF reabsorption, SLP could decrease injection burden in selected cases.

Keywords

Diabetic retinopathy, Diabetic macular edema, Subthreshold micropulse laser, Non damaging retinal laser, Retinal photocoagulation

Area

CLINICAL CASE

Authors

RENATO MAGALHAES PASSOS, FERNANDO KORN MALERBI, MARINDIA ROCHA, MAURICIO MAIA, MICHEL EID FARAH