Changes in the macrophage-like cells following progression and treatment of diabetic macular edema.

Purpose: Macrophage-like cells (MLCs) in the vitreoretinal interface are involved in angiogenesis and retinal homeostasis. This study investigated the changes in the MLCs at the vitreoretinal interface using optical coherence tomography angiography (OCTA) with progression of diabetic retinopathy (DR) and treatment response.

Methods: This cross-sectional, retrospective, observational study involved 86 eyes, categorized into four groups: Diabetes Mellitus without DR (n = 17), DME without treatment (n = 22), DME with anti-VEGF (n = 23), and DME with Dexamethasone (n = 24). The MLCs were imaged in the vitreoretinal interface slab 3 micron from the internal limiting membrane in OCTA. The images were processed with Image J and overlaid on the angiography en face image.

Results: Significant differences in MLC count (P = 0.038), MLC density (P = 0.007), and central subfield thickness (CST) (P = 0.000) were observed with increasing severity and progression from no DR to DME. Both anti-VEGF and DEX treatment were associated with significant reduction in MLC count (P = 0.000, 0.002), MLC density (P = 0.000, 0.002), and CST (P = 0.008, 0.030) A positive significant correlation was noted between MLC density and change in BCVA and CST. No significant difference was noted between anti-VEGF and DEX groups.

Conclusions: MLCs increase with worsening DR and show reduction with treatment response with direct correlation with BCVA and CST. MLCs can act as a surrogate marker for treatment response in DME.