![]() ![]() These morphologic features have been associated with growth of the neovascular lesion, but reliable OCTA markers or predictors of disease activity and response to therapy are lacking. In patients with AMD, OCTA can identify morphologic differences that indicate the maturity of the neovascularization. In neovascular disorders, OCTA can detect MNV in a wide range of conditions, including AMD, myopia, multifocal choroiditis, panuveitis, presumed ocular histoplasmosis syndrome, pseudoxanthoma elasticum, and placoid diseases. Choriocapillaris (CC) flow deficits can be identified in patients with early and intermediate dry AMD, indicating that CC ischemia is an important driving force in the development and progression of the disease. ![]() OCTA is also an effective tool to quantitate choroidal ischemia in dry AMD. In placoid spectrum diseases-such as acute posterior multifocal placoid pigment epitheliopathy and persistent placoid maculopathy-OCTA can effectively illustrate inner choroidal ischemia and can help physicians monitor for progression and response to treatment. OCTA also provides a greater understanding of the choroid in retinal disease because of its ability to better capture the presence of choroidal ischemia and identify macular neovascularization (MNV). 4,7 These findings illustrate the new insights that en face OCT and OCTA have provided into both pathologic and normal retinal vascular states. In more severe cases, PAMM can become more diffuse, and the ischemia can extend into the inner retina closer to the arteriole pole, a mechanism recently described as the ischemic cascade. 5,6 This initially develops in the region of the veins and is referred to as perivenular PAMM with en face OCT. Specifically, patients with mild forms of retinal vein occlusion can initially present with localized INL hyperreflectivity on OCT (ie, paracentral acute middle maculopathy ) with corresponding DCP flow deficit on OCTA. 3,4 In contrast, OCTA can localize the exact layer of ischemia in patients with acute retinal vein and artery occlusions. The DVC is difficult to capture with FA, which is primarily helpful to evaluate the SVC. The deep vascular complex (DVC) comprises the intermediate retinal capillary plexus and the deep retinal capillary plexus (DCP) located in the inner and outer borders of the inner nuclear layer (INL), respectively. The superficial vascular complex (SVC) includes the nerve fiber layer capillary plexus and the superficial retinal capillary plexus (SCP) located between the nerve fiber layer and the inner plexiform layer. ![]() The normal retinal vasculature is composed of four parallel capillary plexuses divided into two major circulations. The depth-resolved capabilities of OCTA facilitate identification and isolation of the retinal vasculature in both normal and pathologic states that are poorly differentiated by fluorescein angiography (FA). The surrounding static tissue remains unchanged on OCT during these short intervals, and the decorrelation information can then be projected in a 2D en face image segmented through the layers of the retina and choroid. With the use of dense volumetric OCT scans, OCTA can detect change (ie, decorrelation) in the OCT signal over very short time periods based on red blood cell motion. OCT angiography (OCTA) is a safe, noninvasive imaging modality that provides depth-resolved imaging of the retinal and choroidal vasculature. Several types of artifacts have been described during acquisition of OCTA images, the most significant being motion, shadow, projection, and pseudoflow artifact.OCTA is a valuable resource to detect macular neovascularization in a wide range of conditions, including AMD, myopia, presumed ocular histoplasmosis syndrome, multifocal choroiditis, panuveitis, pseudoxanthoma elasticum, and placoid diseases.OCT angiography (OCTA) provides depth-resolved imaging of the retinal vasculature in both normal and pathologic states. ![]()
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