Handheld, rapidly switchable, anterior/posterior segment swept source optical coherence tomography probe

Abstract

Abstract:We describe the first handheld, swept source optical coherence tomography (SSOCT) system capable of imaging both the anterior and posterior segments of the eye in rapid succession. A single 2D microelectromechanical systems (MEMS) scanner was utilized for both imaging modes, and the optical paths for each imaging mode were optimized for their respective application using a combination of commercial and custom optics. The system has a working distance of 26.1 mm and a measured axial resolution of 8 μm (in air). In posterior segment mode, the design has a lateral resolution of 9 μm, 7.4 mm imaging depth range (in air), 4.9 mm 6dB fall-off range (in air), and peak sensitivity of 103 dB over a 22° field of view (FOV). In anterior segment mode, the design has a lateral resolution of 24 μm, imaging depth range of 7.4 mm (in air), 6dB fall-off range of 4.5 mm (in air), depth-of-focus of 3.6 mm, and a peak sensitivity of 99 dB over a 17.5 mm FOV. In addition, the probe includes a wide-field iris imaging system to simplify alignment. A fold mirror assembly actuated by a bi-stable rotary solenoid was used to switch between anterior and posterior segment imaging modes, and a miniature motorized translation stage was used to adjust the objective lens position to correct for patient refraction between 12.6 and + 9.9 D. The entire probe weighs less than 630 g with a form factor of 20.3 x 9.5 x 8.8 cm. Healthy volunteers were imaged to illustrate imaging performance. J. G. Fujimoto, "Handheld ultrahigh speed swept source optical coherence tomography instrument using a MEMS scanning mirror," Biomed. ©2015 Optical Society of America

New Frontiers in Retinal Imaging

“…The handheld SD-OCT can assist with the monitoring and evaluation of hereditary maculopathies [72,73] . The upgraded handheld OCT is capable of imaging both the anterior and posterior segments of the eye in rapid succession [74] . Another exciting application of OCT is the potential use of intraoperative OCT (iOCT) during surgery, especially for vitreoretinal surgery.…”

Handheld spectrally encoded coherence tomography and reflectometry for motion-corrected ophthalmic optical coherence tomography and optical coherence tomography angiography

“…20,22,25,26 Both handheld OCT and multimodal ophthalmic imaging probes have been demonstrated using resonant or MEMS scanners to reduce size and increase scan speeds; however, these can have limited FOVs, nonlinear scan trajectories that require additional postprocessing, and different frame rates for each modality, thereby lacking temporal coregistration. 27,28 We address the aforementioned limitations of existing multimodal handheld ophthalmic probes by using spectrally encoded coherence tomography and reflectometry (SECTR), which integrates OCT with spectrally encoded reflectance (SER) imaging. [29][30][31] While conventional SLO uses pointscan illumination and confocal detection, SER uses line-scan illumination by spectrally dispersing a broadband light source and encoding spatial position as a function of wavelength.…”

Effective bidirectional scanning pattern for optical coherence tomography angiography

“…Various lateral scanning devices, such as dual-axis galvanometer-based scanners (GSs) [5][6][7][8] and microelectromechanical (MEMS) based resonant scanners [9][10][11][12][13], have been utilized to achieve high speed volumetric OCT imaging. Among them, GSs are the most commonly utilized devices for lateral scanning in OCT imaging techniques because of advantageous features such as precision positioning, controllable scanning frequency, large angle of scan, and a compact device at a reasonable cost.…”