Ultra-widefield optical coherence tomography angiography in diabetic retinopathy: from retinal lesions to choroidal...

Diabetic retinopathy (DR) continues to represent one of the principal etiologies of visual impairment among working-age populations, and the escalating global burden of diabetes mellitus suggests that this challenge will likely intensify in the coming decades. Conventional diagnostic modalities, most notably fluorescein angiography (FA), have long been employed as reference standards in clinical practice; nevertheless, these approaches are hampered by inherent drawbacks, including their invasive nature and the absence of depth-resolved structural information. The advent of optical coherence tomography angiography (OCTA) has provided a compelling non-invasive alternative capable of delivering depth-stratified vascular visualization. Subsequent technological refinements have yielded ultra-widefield (UWF) OCTA, which substantially extends the imaging field of view and affords detailed examination of the peripheral retinal vasculature that previously remained beyond the reach of conventional acquisition systems. The present review synthesizes current evidence regarding the clinical utility of UWF-OCTA in DR, with particular emphasis on its capacity to identify and characterize key retinal microvascular lesions, encompassing neovascularization (NV), non-perfusion areas (NPAs), microaneurysms (MAs), and intraretinal microvascular abnormalities (IRMAs). The vitreoretinal interface (VRI) slab for detecting NV, emerging choroidal metrics, and a comparison between UWF-OCTA and UWF-FA are also discussed. The evidence suggests that UWF-OCTA detects NV with high sensitivity and specificity, compares favorably to FA, and offers unique advantages, although limitations such as segmentation errors and a smaller field of view must be acknowledged. UWF-OCTA appears to be a promising non-invasive tool for DR diagnosis and monitoring, potentially complementing rather than completely replacing conventional angiography.