Publication Exclusive: OCT angiography a promising imaging modality for evaluation of microvasculopathy

OCT angiography, or OCT-A, was recently developed to provide three-dimensional noninvasive viewing of the retinal and choroidal vasculature and blood flow estimation at the microcirculation level. OCT-A is based on mapping erythrocyte movement over time by comparing sequential OCT B-scans at a given cross-section. OCT-A has now been explored to study different eye diseases including choroidal neovascularization, polypoidal choroidal vasculopathy, diabetic retinopathy, macular telangiectasia, glaucoma and retinal venous occlusion. This is an exciting era in evaluation of microvasculopathy.Fluorescein angiography (FA) and indocyanine green angiography (ICGA) are considered the gold standard for imaging the retinal and choroidal vasculature. However, they are invasive and time-consuming and provide only two-dimensional image analysis without quantifiable parameters. Furthermore, they cannot separately visualize the intraretinal structures of the major capillary networks. The ability to detect microvasculature alterations has also been limited by the superposition of the capillary networks and leakage in FA. OCT-A can be obtained with both spectral-domain OCT and swept-source OCT technologies. There are several key advantages of OCT-A over traditional FA and ICGA.