SignificanceHandheld optical coherence tomography (HH-OCT) systems enable point-of-care ophthalmic imaging in bedridden, uncooperative, and pediatric patients. Handheld spectrally encoded coherence tomography and reflectometry (HH-SECTR) combines OCT and spectrally encoded reflectometry (SER) to address critical clinical challenges in HH-OCT imaging with real-time en face retinal aiming for OCT volume alignment and volumetric correction of motion artifacts that occur during HH-OCT imaging.AimWe aim to enable robust clinical translation of HH-SECTR and improve clinical ergonomics during point-of-care OCT imaging for ophthalmic diagnostics.ApproachHH-SECTR is redesigned with (1) optimized SER optical imaging for en face retinal aiming and retinal tracking for motion correction, (2) a modular aluminum form factor for sustained alignment and probe stability for longitudinal clinical studies, and (3) one-handed photographer-ergonomic motorized focus adjustment.ResultsWe demonstrate an HH-SECTR imaging probe with micron-scale optical-optomechanical stability and use it for in vivo human retinal imaging and volumetric motion correction.ConclusionsThis research will benefit the clinical translation of HH-SECTR for point-of-care ophthalmic diagnostics.
Microscope-integrated intraoperative optical coherence tomography (iOCT) allows for depth-resolved volumetric imaging during ophthalmic surgery. Real-time visualization of iOCT data is conventionally displayed on an external monitor or heads-up display (HUD) optically coupled to surgical oculars. Here, we demonstrate a digital micromirror device (DMD) based HUD that overcomes contrast limitations of existing intraocular HUDs. Our DMD-HUD will enable high resolution display of iOCT data and contextual overlays for real-time intraoperative feedback and during ophthalmic surgery.
Real-time ophthalmic surgical decision-making benefits from volumetric visualization from intraoperative optical coherence tomography and from quantification of retinal structures during surgery. Surgeons typically rely on predetermined measurements and qualitative metrics to perform delicate operations, such as subretinal microliter volume injections for drug delivery and gene therapy. Here, we present a quantitative method for volumetric estimation of subretinal injection volume based on intraocular reference features with intraoperative optical coherence tomography for use during ophthalmic surgery. We predict this method will improve the accuracy of subretinal injections and provide better ergonomics and surgical workflow over current methods for ophthalmic surgery.
Compensation of ocular refractive error is essential for obtaining high-quality OCT/OCTA retinal images for retinal diagnostics across patients with different refractive power. During point-of-care ophthalmic imaging with handheld OCT systems, the clinical ergonomics of operator-driven focal adjustments to accommodate refractive error can disrupt clinical workflow. Here, we present a closed-loop automated hands-free focus tracking method to overcome limitations of conventional manual focus adjustment, and demonstrate its performance when integrated with our handheld spectrally encoded coherence tomography and reflectometry (HH-SECTR) probe. We predict automated focus tracking will improve clinical ergonomics for more efficient point-of-care ophthalmic imaging.
Traditional benchtop OCT systems require upright patient fixation and often impede ophthalmic imaging in bedridden, uncooperative, and pediatric patients. Point-of-care OCT systems have demonstrated ophthalmic imaging in supine patients. However, manually aligning and correcting for refractive power variations between patient eyes to ensure optimal image quality can be clinically cumbersome with point-of-care imaging systems. Here, we demonstrate our improved handheld spectrally encoded coherence tomography and reflectometry (HH-SECTR) imaging probe with mechanical focus-adjust and improved optical throughput in a clinically robust form-factor. SECTR uses spatiotemporally co-registered multimodal spectrally encoded reflectometry (SER) and OCT acquisition for volumetric motion-correction and retinal mosaicking. Our previous HH-SECTR prototype had three major limitations: 1) poor alignment stability caused by reduced mechanical stiffness in a completely rapid-prototyped resin body; 2) lossy SER optical throughput; and 3) manual focus adjust that was cumbersome during point-of-care imaging. Here, we demonstrate optical and optomechanical design improvements to address these limitations, including a modular aluminum probe chassis and increased optical power throughput for sustained system alignment and imaging performance. We have also incorporated a mechanical focusing subsystem to correct refractive errors, which can be integrated with our acquisition software for hands-free focus tracking. We demonstrate in vivo human retinal imaging, and mechanical focusing capabilities using a stationary model eye and stepping through ± 10 diopters focal shift. We predict the addition of focusing capabilities and design improvements in form-factor and optical throughput to our HH-SECTR probe will benefit clinical translation and point-of-care multimodal OCT imaging.
Ophthalmic surgery is conventionally performed under white-light microscopy which has limited benefit for identifying tissue layers and providing depth-resolved feedback. Intraoperative optical coherence tomography (iOCT) has enabled depth-resolved intraoperative imaging of retinal microstructures. Recent advancements have enabled faster imaging speeds and video-rate, volumetric iOCT imaging of surgical dynamics, and en face retinal imaging that enables robust visualization of surgical instruments for tool-tracking. Here, we demonstrate our intraoperative spectrally encoded coherence tomography and reflectometry imaging (iSECTR) system with enhanced optical throughput and mechanical focus-adjust in a more clinically robust form-factor. iSECTR uses spatiotemporally co-registered multimodal spectrally encoded reflectometry (SER) and OCT for automated en face instrument-tracking and volumetric visualization of surgical dynamics. Here, we demonstrate several optical and optomechanical design improvements, which include the design of a modular aluminum skeleton to house SECTR imaging optics and optomechanics throughput to maintain system alignment and imaging performance. Mechanical focusing capabilities were integrated to accommodate for any adjustments to surgical oculars made by the ophthalmic surgeon before surgery for simultaneous optimal imaging in both iSECTR and the ocular view of the surgical field. We demonstrate ex vivo cornea and retinal imaging, and mechanical focusing capabilities using a stationary model eye and stepping through ± 10 diopters focal shift. We predict the addition of focusing capabilities and improvements in form-factor and optical throughput to our iSECTR system will benefit surgical translation and workflow for ophthalmic surgeries.
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