Diabetic foveal neovascularization is associated with diminished subfoveal choroidal flow on optical coherence tomography angiography.

Abstract

Objective: To evaluate the role of retinal and choriocapillaris blood flow in the development of diabetic foveal neovascularization (DFN) using optical coherence tomography angiography (OCTA).

Methods: Eyes with proliferative diabetic retinopathy (PDR) and DFN underwent OCTA imaging; defined as surface retinal neovascularization within the central foveal 1 mm diameter circle. 3 × 3 and 6 × 6 mm² choriocapillaris and superficial and deep retinal capillary plexus (SCP and DCP) slabs were extracted to evaluate adjusted flow index (AFI) as a surrogate for blood flow. For choriocapillaris flow; total, subfoveal and extrafoveal AFI were assessed, while only total AFI was calculated for SCP and DCP. These findings were compared to healthy controls and eyes with PDR with no DFN.

Results: 18 eyes of 18 patients were included in each of the 3 groups: healthy controls, PDR with and without DFN. Choriocapillaris AFI was significantly lower in PDR with DFN than healthy controls in all but the 6 × 6 mm² extrafoveal AFI (p < 0.01). PDR with DFN also showed a lower AFI compared to eyes without DFN, but only in the 3 × 3 mm² total and subfoveal AFI (p = 0.01). SCP and DCP AFI were not statistically significant.

Conclusions: Our findings suggest that choroidal hypoperfusion may be a potential driving factor for the development of DFN. The detection of these changes in the smaller scans of the total and subfoveal areas suggests a rather exaggerated and localized subfoveal distribution of ischaemia. Larger longitudinal studies are needed to explore the use of subfoveal choroidal AFI as a prognostic sign for DFN.