Mean macular intercapillary area in eyes with diabetic macular oedema after anti-vascular endothelial growth factor therapy and its association with treatment response

Background To evaluate the changes in the mean macular intercapillary area (ICA) from sequential enface optical coherence tomography angiography (OCTA) images following intravitreal anti-vascular endothelial growth factor (VEGF) therapy in initially treatment-naive eyes with diabetic macular oedema (DME). Methods In this multicentre retrospective study, 6 x 6 and 3 x 3 mm customised, total retinal projection enface OCTA images were collected and processed for quantitative assessment of ICA by a customised MATLAB software. Measurements were done in concentric regions centred on the fovea-with the exclusion of foveal avascular zone (FAZ)-in 0.5 mm diameter increments as well as within the intervening rings. Results In this study, 6 x 6 mm OCTA images from 46 eyes of 29 patients, and 3 x 3 mm OCTA images from 23 eyes of 15 patients were included. There was no significant change in mean ICA after treatment in either scan size or in any measurement regions (all p > 0.05). Multivariate analysis revealed that baseline BCVA was significantly correlated with the visual outcome (p = 0.039). Additionally, after correction for age, baseline central retinal thickness (CRT), baseline BCVA, and retinopathy severity, mean ICA in the 1.5 mm circle was found to be a significant predictor of post treatment CRT, (p = 0.006). Conclusions Absence of significant change in mean ICA after a minimum of three intravitreal anti-VEGF injections, may indicate that, in the short term, anti-VEGF injections neither impair nor improve macular perfusion in DME. Baseline BCVA was found to be a robust predictor of functional outcome, while inner mean ICA was a significant predictor for macular thickness outcomes.

Automated summary

Evaluation of mean macular intercapillary area (ICA) changes following intravitreal anti-vascular endothelial growth factor (VEGF) therapy in initially treatment-naive eyes with diabetic macular oedema (DME) showed no significant improvement in macular perfusion in the short term, indicating that anti-VEGF injections may not have a significant impact on macular blood flow in DME patients. Baseline best-corrected visual acuity (BCVA) was found to be a strong predictor of functional outcome, while inner mean ICA was a significant predictor for macular thickness outcomes.