Neovascular age-related macular degeneration (AMD), characterized by the presence of choroidal neovascularization (CNV), accounts for the majority of AMD-related vision loss. Optical coherence tomography (OCT) has become the most frequently used test for AMD evaluation; however, fluorescein angiography (FA), which requires an invasive intravenous dye injection, is needed for initial CNV diagnosis. Using a high-speed OCT system, we have developed an algorithm called split-spectrum amplitude decorrelation angiography (SSADA) to non-invasively image and measure both retinal and choroidal blood flow. Preliminary results showed that OCT angiography successfully imaged CNV tissue. The goal of the proposed project is to improve OCT angiography technology and determine its role in AMD evaluation and management. 1. Improve imaging of choroidal neovascularization (CNV) with OCT angiography. Algorithmic improvements in angiography, segmentation, registration, and automation are planned. 2. Quantify inner retinal, outer retinal (CNV), and choroidal flow using OCT angiography for neovascular AMD. OCT angiogram will be calibrated by physical flow phantoms. Fully automated quantification of the blood flow within different vascular beds will be developed including a novel CNV area and flow index product. Automated software will be developed to quantify intraretinal fluid volume, subretinal fluid volume, and central retinal thickness, all from a single OCT angiography scan. 3. Conduct a cross-sectional study to use OCT angiography in the initial evaluation of CNV. The specificity and sensitivity of OCT angiography to detect CNV will be determined in 60 neovascular AMD and 60 normal age-matched control subjects. 4. Conduct a longitudinal study of OCT angiography in the evaluation of neovascular AMD subjects undergoing treatment. The utility of OCT angiography for assessing CNV activity while undergoing treatment will be evaluated in 25 neovascular AMD subjects over the course of one year. 5. Conduct a longitudinal study of OCT angiography to determine if reduced choroidal flow is a risk factor for CNV development. The utility of OCT angiography for identifying reduced choroidal flow as a potential risk factor for CNV development and the possibility of OCT angiography in detecting pre-clinical CNV will be evaluated with 60 high-risk eyes at 6-month intervals for three years. We expect that our results will show OCT angiography can provide clinically relevant information assisting with CNV diagnosis, assessing CNV activity while undergoing treatment, and aid with surveillance for dry AMD eyes at risk for CNV. OCT angiography has the potential to reduce (if not replace) the need for FA.
Timely diagnosis and treatment of choroidal neovascularization (CNV) is imperative to prevent vision loss from neovascular age-related macular degeneration (AMD). Currently, fluorescein angiography, an invasive test, is the gold standard to diagnose CNV. We will develop OCT angiography to enhance the capabilities of currently utilized OCT, a safe and non-invasive diagnostic test. OCT angiography will aid in our understanding of neovascular AMD and will provide new information to help clinicians with diagnosis and management decisions.
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