Vessel density changes on optical coherence tomography angiography after vascular endothelial growth factor inhibitor treatment for diabetic macular edema

Objective: To evaluate the changes in macular vessel density after treatment with vascular endothelial growth factor (VEGF) inhibitors in centre-involving diabetic macular edema (DME) and to compare these changes between anatomical responders and non-responders.

Materials and Methods: Retrospective study of 22 eyes with centre-involving DME. All eyes had 3 consecutive administrations of VEGF inhibitors. Optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) of the macula with manual adjustment of segmentation lines were performed at baseline and after treatment. Vessel density in the central and parafoveal regions of the superficial (SCP) and deep capillary plexus (DCP) were measured at baseline and after treatment. The vessel density and its changes were subsequently compared between anatomical responders and non-responders as defined by the central subfield thickness (CST) changes.

Results: Overall, there were no significant differences in the vessel density in the central and parafoveal regions of the SCP and DCP at baseline and after treatment. After categorisation by the anatomical response, 12 eyes were responders (CST decreased by 173.7±47.7 µm) and 10 eyes were non-responders (CST increased by 20.8±38.9 µm) (P<0.0001). There were no corresponding significant differences in the vessel density and its changes between the responders and non-responders at the SCP and DCP after treatment.

Conclusion: There were no significant changes in macular vessel density after the early stages of VEGF inhibitor treatment for DME, and there was no relationship with the anatomical response. The effect of VEGF inhibitors in DME treatment therefore may not be related to increasing vessel density.