Anatomical and functional outcomes of subthreshold micropulse laser versus intravitreal ranibizumab injection in treatment of diabetic macular edema

BACKGROUND: To compare the therapeutic effects of subthreshold micropulse laser (SML) versus intravitreal injection of ranibizumab in treatment of diabetic macular edema (DME) both anatomically using optical coherence tomography (OCT) and functionally using best corrected visual acuity (BCVA) and multifocal electroretinogram (mfERG). METHODS: his study was an interventional prospective randomized comparative study. The study included 120 eyes classified into 3 groups: Group 1 included 40 eyes of 28 patients treated by SML laser, group 2 included 40 eyes of 32 patients treated by intravitreal injection of ranibizumab, and group 3 (control group for mfERG) included 40 eyes of 20 patients with diabetes mellitus (DM) of more than 10 year duration with no signs of diabetic retinopathy (DR). BCVA measurements, OCT and mfERG were done for the cases before and after interference and were followed up for 6 months RESULTS: By the end of the follow up period, BCVA significantly improved by 31% in group 1 vs 93% in group 2 with a statistically highly significant difference between the two groups (p value < 0.001). There was also a significant decrease in central subfield thickness in both groups with more reduction in group 2 compared with group 1 (p value < 0.001). There was a significant improvement in P1 amplitude of mf-ERG in group 2 (p value < 0.002) with no significant improvement in group 1. There was a significant decrease in P1 implicit time in group 2 (p value < 0.001) while there was no significant decrease in group1. CONCLUSIONS: Intravitreal injection of ranibizumab is a superior treatment modality for DME compared with SML regarding both anatomical and functional outcomes. Trial registration: This study has been approved by the local ethical committee of faculty of medicine of Minia University and retrospectively registered at the clinical trial gov. with Identifier: NCT04332133.