COMPARING FUNCTIONAL AND VASCULAR LAYER OUTCOMES OF LASER PHOTOCOAGULATION VERSUS SUBTHRESHOLD MICROPULSE LASER FOR DIABETIC MACULAR EDEMA

Abstract

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