Abstract
A high-speed (100 kHz A-scans/s) complex conjugate resolved 1 μm swept source optical coherence tomography (SS-OCT) system using coherence revival of the light source is suitable for dense three-dimensional (3-D) imaging of the anterior segment. The short acquisition time helps to minimize the influence of motion artifacts. The extended depth range of the SS-OCT system allows topographic analysis of clinically relevant images of the entire depth of the anterior segment of the eye. Patients with the type 1 Boston Keratoprosthesis (KPro) require evaluation of the full anterior segment depth. Current commercially available OCT systems are not suitable for this application due to limited acquisition speed, resolution, and axial imaging range. Moreover, most commonly used research grade and some clinical OCT systems implement a commercially available SS (Axsun) that offers only 3.7 mm imaging range (in air) in its standard configuration. We describe implementation of a common swept laser with built-in k-clock to allow phase stable imaging in both low range and high range, 3.7 and 11.5 mm in air, respectively, without the need to build an external MZI k-clock. As a result, 3-D morphology of the KPro position with respect to the surrounding tissue could be investigated in vivo both at high resolution and with large depth range to achieve noninvasive and precise evaluation of success of the surgical procedure.
Highlights
The cornea and anterior segment imaging system was first introduced using time-domain optical coherence tomography (OCT) (Carl Zeiss, Inc., Dublin, California), with a light source operating at a central wavelength of 830 nm, and was able to reconstruct cross-sectional images (B-scans) of only a small portion of the anterior segment, with an imaging speed of 100 to 400 A-scans∕s1,2 In 2000,3an OCT system was implemented with a 1310 nm superluminescent diode capable of covering a larger portion of the anterior segment, including the entire cross-sectional structure of the cornea
We report on the development and implementation of a switchable imaging depth range swept source optical coherence tomography (SS-OCT) system (3.7 to 11.5 mm in air) with 4.5 μm axial resolution, higher image acquisition speed (100 kHz), and deep tissue penetration
We demonstrated a high-speed complex conjugate resolved 1 μm swept source (SS)-OCT system using coherence revival applied to ophthalmic imaging of the human anterior segment
Summary
The cornea and anterior segment imaging system was first introduced using time-domain optical coherence tomography (OCT) (Carl Zeiss, Inc., Dublin, California), with a light source operating at a central wavelength of 830 nm, and was able to reconstruct cross-sectional images (B-scans) of only a small portion of the anterior segment, with an imaging speed of 100 to 400 A-scans∕s1,2 In 2000,3an OCT system was implemented with a 1310 nm superluminescent diode capable of covering a larger portion of the anterior segment, including the entire cross-sectional structure of the cornea. The introduction of Fourier-domain OCT,[4,5,6] due to the advantage of increased sensitivity and acquisition speed,[7,8,9] permitted three-dimensional (3-D) imaging with rather short depth range (∼2 mm in tissue).[10,11] Originally, commercial spectrometer-based Fourier-domain OCT systems (spectral OCTSD-OCT) had been designed for retinal imaging and offered an axial resolution of 3 to 7 μm and imaging speeds of 20,000 to 50,000 A-scans∕s They are not able to provide adequate assessment of anterior and posterior corneal. A robust high-speed volumetric SS-OCT system that extends
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