The effect of intravitreal anti-VEGF injections on choroidal vascular index in patients with diabetic macular edema.

Purpose: This study aims to examine and compare the effects of intravitreal bevacizumab injection (IVB) at subfoveal 1500 micron (μm) and submacular 6000 μm in patients with diabetic macular edema (DME).

Methods: Fifty eyes of 45 patients with DME who completed six doses of IVB were included in the study group, and 50 eyes of 42 patients who had diabetic retinopathy (DR) but did not receive any treatment were included in the control group. Central macular thickness (CMT), central choroidal thickness (CCT), subfoveal and total choroidal area (TCA), and choroidal vascular index (CVI) were calculated and their changes at zero, three and six months were evaluated.

Results: At baseline, CVI was significantly lower in both the subfoveal and total macular areas in the study group (p = 0.004, p = 0.003). In the study group, a significant decrease was observed in CVI between zero and six months in the subfoveal area (p = 0.001). In the submacular area, the decrease in CVI in the study group was significant between zero to three months and zero to six months. There was moderate correlation between measurements of CVI in the subfoveal and total macular areas (r = 0.66, p < 0.001).

Conclusion: These findings indicate that intravitreal bevacizumab injection reduces the CVI and the effects of intravitreal anti-VEGF on CVI emerge earlier and more prominently in the submacular 6000 µm area.