In OCTA, resolution of retinal capillaries is limited by physical numerical aperture of human eye and the subject’s ocular aberrations. Adaptive optics OCTA has been demonstrated in instruments with large numerical aperture, originally designed for the visualization of retinal cells. In this work, we propose a high-speed, spectral domain sensorless adaptive optics OCTA instrument with a 3-mm beam to image retinal capillaries of all three retinal plexuses simultaneously, with high axial and lateral resolution. A novel and fast hill climbing algorithm was applied on the amplitude of six low-order Zernike modes to minimize ocular aberrations based on maximizing en face merit functions of the layer of interest computed in real time.
Detecting and quantifying choroidal neovascularization (CNV) is essential for the diagnosis of neovascular age-related macular degeneration (AMD). Projection-resolved OCT angiography (PR-OCTA) has enabled both en face and volumetric visualization of CNV. However, previously described CNV detection methods only quantify CNV that was already diagnosed, and were unable to identify CNV form unknown inputs . Previous methods were also limited by artifacts. A fully automated CNV diagnosis and quantification algorithm using convolutional neural networks (CNNs) was developed. It was able to diagnose CNV and output CNV membrane and vessel area from retinal structural and angiographic images.
Using a commercial available 200K swept source laser, we demonstrated high resolution wide field angiographic imaging of human retinal. 8mm by 8mm and 10mm by 6mm retina areas were imaged in a single scan within 4 seconds. By montaging four 10 x 6mm scan, 10 x 20mm wide field OCT angiography images were demonstrated.
We propose a three-dimensional (3-D) registration method to correct motion artifacts and construct the volume structure for angiographic and structural optical coherence tomography (OCT). This algorithm is particularly suitable for the nonorthogonal wide-field OCT scan acquired by a ultrahigh-speed swept-source system (>200 kHz A-scan rate). First, the transverse motion artifacts are corrected by the between-frame registration based on en face OCT angiography (OCTA). After A-scan transverse translation between B-frames, the axial motions are corrected based on the rebuilt boundary of inner limiting membrane. Finally, a within-frame registration is performed for local optimization based on cross-sectional OCTA. We evaluated this algorithm on retinal volumes of six normal subjects. The results showed significantly improved retinal smoothness in 3-D-registered structural OCT and image contrast on en face OCTA.
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