Small animal models of retinal diseases are important to vision research, and noninvasive high resolution in vivo rodent retinal imaging is becoming an increasingly important tool used in this field. We present a custom Fourier domain optical coherence tomography (FD-OCT) instrument for high resolution imaging of mouse retina. In order to overcome aberrations in the mouse eye, we incorporated a commercial adaptive optics system into the sample arm of the refractive FD-OCT system. Additionally, a commercially available refraction canceling lens was used to reduce lower order aberrations and specular back-reflection from the cornea. Performance of the adaptive optics (AO) system ...

We present in vivo noninvasive retinal and choroidal perfusion maps with phase-variance optical coherence tomography (pvOCT). We acquired a pvOCT volumetric data set of a normal subject and visualized blood circulation in the retina and the choroid. En face projection views of the retina as well as the choroid were generated from a manually segmented volumetric data set. In addition, the processed pvOCT images were compared to current standard imaging modalities used for retinal and choroidal vasculature visualization in clinical settings, including fluorescein angiography (FA) and indocyanine green angiography (ICGA).

We present a high-speed complex conjugate resolved 1 μm swept source optical coherence tomography [SS-OCT] system using coherence revival of the light source for clinical imaging of the anterior segment of the eye. High-speed of 100,000 A-scans/sec and 1 μm imaging window of OCT permits dense 3D imaging of the anterior segment, minimizing the influence of motion artifacts and deep penetration of images for topographic analysis. The swept laser performance with internal clocking was adapted to achieve extended imaging depth requirements. The feasibility of our instrument for visualization of the anterior segment of patients with the Boston Keratoprosthesis ...

We document our latest work in developing a new eye model with a solid-state cornea and liquid filled anterior chamber designed for demonstrating, validating and comparing anterior chamber ophthalmic Optical Coherence Tomography (OCT) instruments, corneal topographers, and Scheimpflug cameras. Anterior chamber eye model (ACEM) phantoms can serve a variety of purposes, including demonstrating instrument functionality and performance in both the clinic and exhibit hall, validating corneal layer thickness measurements from different commercial instruments and as an aide for the R and D engineer and field service technician in the development and repair of instruments, respectively. The ideal eye model for ...

This paper describes a novel optical method for label-free quantitative imaging of cerebral blood flow (CBF) and intracellular motility (IM) in the rodent cerebral cortex. This method is based on a technique that integrates dynamic light scattering (DLS) and optical coherence tomography (OCT), named DLS–OCT. The technique measures both the axial and transverse velocities of CBF, whereas conventional Doppler OCT measures only the axial one. In addition, the technique produces a three-dimensional map of the diffusion coefficient quantifying nontranslational motions. In the DLS–OCT diffusion map, we observed high-diffusion spots, whose locations highly correspond to neuronal cell bodies and ...

University of California at Davis received a 2012 a NIH Grant for $211,184 for Functional Optical Coherence To...

We acquired in vivo images of the human optic nerve head (ONH) using an adaptive optics—optical coherence tomography (AO-OCT) system. In order to improve imaging of the lamina cribrosa in the ONH with high lateral resolution and sensitivity, we implemented a complex conjugate artifact-free Fourier domain OCT (Fd-OCT) acquisition scheme with a reference arm-based phase shifting method. This allowed positioning of the lamina cribrosa structures near the zero path length difference where AO-OCT imaging achieves highest sensitivity. Implementation of our complex conjugate artifact removal (CCR) method required constant phase shifts between consecutive axial scans (A-scans), generated by continuous beam ...

Organs such as the heart and brain possess intricate fiber structures that are best characterized with three-dimensional imaging. For instance, diffusion-based, magnetic resonance tractography (MRT) enables studies of connectivity and remodeling during development and disease macroscopically on the millimeter scale. Here we present complementary, high-resolution microscopic optical coherence imaging and analysis methods that, when used in conjunction with clearing techniques, can characterize fiber architecture in intact organs at tissue depths exceeding 1 mm. We anticipate that these techniques can be used to study fiber architecture in situ at microscopic scales not currently accessible to diffusion magentic resonance (MR), and thus ...

Dr. Vivek Srinivasan will join the Biomedical Engineering Department faculty as an Assistant Professor, effective July 1, 2012. He has a B.S. from Stanford University and a Ph.D. from MIT. Dr. Srinivasan has a particular focus on neural engineering and also works in biophotonics and imaging. His particular areas of interest include neurovascular coupling, neuroimaging, non-invasive optical methods for measuring retinal function, rapidly wavelength tunable lasers and swept source Optical Coherence Tomography (OCT), high-speed spectrometers and light sources for ultrahigh resolution spectral / Fourier domain OCT, image segmentation and quantitative analysis, and applications of high-speed high-resolution OCT in biomedical ...

This study explores the structure characteristics of thick glaze, in terms of the case study of Chinese Southern Song Guan (SSG) ware, focusing on the bubble and its media structure, using a novel focus-tracking optical coherence tomography (OCT) system. The OCT images we obtained not only unveil the structural uniqueness of the thick-glaze SSG sample, but also establish a distinguishable structural pattern for aiding authentication. In addition, information revealed in our images provides a logical explanation for the subtle texture and tone of SSG glaze as well as insights into the technologies used in layering and firing these thick glazes.

The rapid development of optical coherence tomography (OCT) and its ophthalmic applications has resulted in the emergence of new laboratory and commercial systems that vary in performance and functionality. The introduction of high-speed imaging capabilities has abrogated the primary limitation of early OCT technology by providing in vivo three-dimensional volumetric reconstructions of both anterior and posterior segments of the human eye within reasonable time constraints. Currently, high-speed swept source OCT technology has made it possible to achieve OCT acquisition speeds of several million A-scans/s. Another direction of OCT development includes the introduction of adaptive optics to imaging of the ...