Progression of diabetic microaneurysms according to the internal reflectivity on structural OCT and visibility on OCT angiography

PURPOSE: To investigate the progression of diabetic microaneurysms (MAs) according to the SD-OCT and OCT Angiography (OCTA) characteristics and to evaluate their influence on the retinal extracellular fluid accumulation at 1 year follow-up in patients with non proliferative diabetic retinopathy (NPDR).

DESIGN: Prospective, observational case series.

METHODS: Fourteen patients with NPDR underwent SD-OCT and OCTA at the baseline and at 1 year follow-up. For all the selected MAs the visibility, the changes of internal reflectivity, graded as hypo-, moderate, or hyper-reflective, and the extracellular fluid accumulation surrounding each MA on SD-OCT at one year were evaluated. The changes in term of visualization at the level either of superficial (SCP) and deep (DCP) capillary plexus and the presence of flow on the corresponding OCTA scan at 1 year were evaluated.

RESULTS: Of 127 MAs selected at the baseline 89 (70%) were still visible on SD-OCT at 1 year. The reflectivity pattern at baseline was strongly associated with extracellular fluid accumulation at 1 year with 18% of hyporeflective vs. 66% of hyperreflective MAs developing extracellular fluid (p=0.004). Among OCTA findings, the presence of flow (p=0.001) the visibility (p<0.001) and the deep location (DCP or both DCP and SCP, p=0.007) were strongly associated with the development of extracellular fluid at 12 months.

CONCLUSIONS: This study suggests an association between the SD-OCT and OCTA characteristics of diabetic MAs and the retinal extracellular fluid accumulation at 1 year. A better interpretation of MAs characteristics could improve the timing and the management of diabetic maculopathy.