Comparing functional and vascular layer outcomes of laser photocoagulation versus subthreshold micropulse laser for diabetic m.

Abstract

To compare the efficacy of conventional laser (CL) and subthreshold micropulse laser (SML) for treating diabetic macular edema in terms of functional outcomes and changes in quantitative metrics for the retinal capillary and choriocapillary vascular layers. Fifty-two eyes from 52 patients with treatment-naïve clinically significant macular edema were randomly assigned to the CL or SML group in a 1:1 ratio. Best-corrected visual acuity, central macular thickness (CMT) and optical coherence tomography angiography (OCT-A) scans were measured at baseline, 1-, 3- and 6-months post-treatment. The SML group showed rapid visual recovery, improving from baseline of 0.320 ± 0.31 logMAR (20/42 Snellen) to 0.270 ± 0.22 logMAR (20/37 Snellen) at 1 month (p = 0.038); and had significant improvements in CMT at 6-month post-treatment (353.88 to 301.00µm, p = 0.005). Statistically significant changes were detected across all OCT-A metrics, including vessel density (VD), vessel length density (VLD), vessel diameter index (VDI) and fractal dimension (FD), at 6 months for both groups in the deep capillary plexus (DCP) and choriocapillary plexus (CCP). SML resulted in early visual recovery and sustained macular thickness improvement in the treatment of DME. Microvascular perfusion parameters, including VD, VLD and FD, improved in the DCP and CCP for both treatment groups at 6-months post-treatment.