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Weiye Song, Wei Yi, ji yi; Wide-field visible light optical coherence tomography (WF-vis-OCT) for human retinal imaging with axial-tracking and dynamic focusing. Invest. Ophthalmol. Vis. Sci. 2020;61(9):PP001.
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Visible light optical coherence tomography (vis-OCT) has drawn increasing attention due to its unique capabilities in structural and functional imaging. Current state-of-the-art human retinal vis-OCT systems have a limited field of view (FOV) due to the curvature of the retina and the system sensitivity roll-off. A wide-field (WF) vis-OCT system is desired to explore the full potential of vis-OCT in clinical applications.
The WF-vis-OCT schematic is shown in Fig.1. Briefly, a supercontinuum laser was used to provide a broadband laser output. The wavelength range from 535-600 nm was selected by two edge filers and divided by a 90/10 fiber coupler. Ten percent of the light was delivered to the sample arm and steered by a pair of galvanometers after passed a collimator and a tunable lens. A custom-designed 2:1 telescope relays the light to the pupil. The reference arm is consisted of a collimator, a ND filter, and dispersion control component, and a retroreflector. The retroreflector was mounted on a galvanometer. The axial-tracking and dynamic focusing is by simultaneous control of the retroreflector position and the tunable lens.
Figure 2 exhibits the WF vis-OCT system’s large (65 degrees) FOV in a healthy volunteer. Using WF vis-OCT, we acquired high-quality (1024 horizontal X 512 vertical) human retinal images in a single continuous scan with minimal motion artifacts at a 50K A-line speed. Thanks to the high resolution enable by vis-OCT, different layers in the outer retina can be visualized clearly, especially both retinal pigment epithelium layer and Bruch’s membrane can be distinguished easily. Two smaller subfields were also acquired to generate high definition enlarged images without changing subject fixation.
To the best of our knowledge, we presented the largest field-of-view vis-OCT human retinal imaging to this date. This device greatly expands the imaging capabilities of vis-OCT in imaging the peripheral retina as well as the macula and the peripapillary region.
This is a 2020 Imaging in the Eye Conference abstract.
Fig. 1 WF vis-OCT system schematic.
Fig.2 WF vis-OCT human retinal image. (a) is WFOV vis-OCT human retina image. (b) is the cross-sectional image corresponding to the yellow line in (a). (c) and (d) is the enlarged image corresponding to the two square locations in (a).
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