Abstract
Histological studies have shown that morphometric changes at the microscopic level of choriocapillaris (CC) occur with aging and disease onset, and therefore may be sensitive biomarkers of outer retinal health. However, visualizing CC at this level in the living human eye is challenging because its microvascular is tightly interconnected and weakly reflecting. In this study, we address these challenges by developing and validating a method based on adaptive optics optical coherence tomography with angiography (AO-OCTA) that provides the necessary 3D resolution and image contrast to visualize and quantify these microscopic details. The complex network of anastomotic CC capillaries was successfully imaged in nine healthy subjects (26 to 68 years of age) and at seven retinal eccentricities across the macula. Using these images, four fundamental morphometric parameters of CC were characterized: retinal pigment epithelium-to-CC depth separation (17.5 ± 2.1 µm), capillary diameter (17.4 ± 2.3 µm), normalized capillary density (0.53 ± 0.08), and capillary length per unit area (50.4 ± 9.5 mm-1). AO-OCTA results were consistent with histologic studies and, unlike OCTA, showed clear delineation of CC capillaries, a requirement for measuring three of the four morphometric parameters. Success in younger and older eyes establishes a path for testing aging and disease effects in larger populations. To the best of our knowledge, this is the first quantitative morphometry of choriocapillaris at the level of individual capillaries in the living human retina.
Highlights
The choriocapillaris (CC) is a dense monolayer of interconnecting capillaries that line the inner choroid and is the blood supply for the overlying retinal pigment epithelium (RPE) and photoreceptors
Visualization of the interconnecting capillaries of CC remains prohibitive owing to the lack of lateral resolution to delineate the vessels. This is problematic in the macula where CC vasculature is most dense. We address these challenges of image resolution and contrast by developing and validating a method based on adaptive optics optical coherence tomography with angiography (AO-OCTA)
Vessels of the choriocapillaris were successfully imaged and registered, and morphometric parameters extracted in all nine subjects and seven retinal eccentricities imaged with AOOCTA
Summary
The choriocapillaris (CC) is a dense monolayer of interconnecting capillaries that line the inner choroid and is the blood supply for the overlying retinal pigment epithelium (RPE) and photoreceptors. CC is fundamental to maintaining visual function and overall health of the outer retina. Histological studies have shown that morphometric changes at the microscopic level of CC occur with aging [1] and disease such as age-related macular degeneration [2,3,4], diabetic retinopathy [5] and glaucoma [6], and detection and monitoring of changes at this scale provide the greatest promise for improved diagnosis and intervention. Visualizing and quantifying CC at this level in the living human eye is challenging because the microvascular is tightly interconnected and weakly reflecting
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
