Model-based optical coherence tomography angiography enables motion-insensitive vascular imaging.

We present a significant step toward ultrahigh-resolution, motion-insensitive characterization of vascular dynamics. Optical coherence tomography angiography (OCTA) is an invaluable diagnostic technology for non-invasive, label-free vascular imaging . However, since it relies on detecting moving cells from consecutive scans, high-resolution OCTA is susceptible to tissue motion, which imposes challenges in resolving and quantifying small vessels.

Near-Histologic Resolution Images of Cervical Dysplasia Obtained With Gabor Domain Optical Coherence Microscopy.

Objective: Histopathology is the criterion standard for evaluating cervical squamous intraepithelial neoplasia (dysplasia). In this pilot feasibility study, we examined whether a novel 3-dimensional imaging device using Gabor-domain optical coherence microscopy (GDOCM) could distinguish features of cervical dysplasia comparable with histopathology.

Methods: A prospective observational pilot study enrolled a small sample of women undergoing loop electrosurgical excision procedure for cervical squamous intraepithelial neoplasia.

Unbiased corneal tissue analysis using Gabor-domain optical coherence microscopy and machine learning for automatic segmentation of corneal endothelial cells.

Significance: An accurate, automated, and unbiased cell counting procedure is needed for tissue selection for corneal transplantation.

Aim: To improve accuracy and reduce bias in endothelial cell density (ECD) quantification by combining Gabor-domain optical coherence microscopy (GDOCM) for three-dimensional, wide field-of-view (1  mm2) corneal imaging and machine learning for automatic delineation of endothelial cell boundaries.

Approach: Human corneas stored in viewing chambers were imaged over a wide field-of-view with GDOCM without contacting the specimens.

Ten Years of Gabor-Domain Optical Coherence Microscopy.

Gabor-domain optical coherence microscopy (GDOCM) is a high-definition imaging technique leveraging principles of low-coherence interferometry, liquid lens technology, high-speed imaging, and precision scanning. GDOCM achieves isotropic 2 μm resolution in 3D, effectively breaking the cellular resolution limit of optical coherence tomography (OCT). In the ten years since its introduction, GDOCM has been used for cellular imaging in 3D in a number of clinical applications, including dermatology, oncology and ophthalmology, as well as to characterize materials in industrial applications.

imaging of corneal nerves and cellular structures in mice with Gabor-domain optical coherence microscopy.

Gabor-domain optical coherence microscopy (GDOCM) demonstrated corneal imaging with cellular resolution and differentiation in mice over a field of view of 1 mm. Contact and non-contact imaging was conducted on six healthy and six hyperglycemic C57BL/6J mice. Cellular resolution in the 3D GDOCM images was achieved after motion correction.

Gabor domain optical coherence microscopy combined with laser scanning confocal fluorescence microscopy.

We report on the development of fluorescence Gabor domain optical coherence microscopy (Fluo GD-OCM), a combination of GD-OCM with laser scanning confocal fluorescence microscopy (LSCFM) for synchronous micro-structural and fluorescence imaging. The dynamic focusing capability of GD-OCM provided the adaptive illumination environment for both modalities without any mechanical movement. Using Fluo GD-OCM, we imaged DsRed-expressing cells in the brain of a transgenic mouse, as well as Cy3-labeled ganglion cells and Cy3-labeled astrocytes from a mouse retina.

Quantitative assessment of human donor corneal endothelium with Gabor domain optical coherence microscopy.

We report on a pathway for Gabor domain optical coherence microscopy (GD-OCM)-based metrology to assess the donor’s corneal endothelial layers ex vivo. Six corneas from the Lions Eye Bank at Albany and Rochester were imaged with GD-OCM. The raw 3-D images of the curved corneas were flattened using custom software to enhance the 2-D visualization of endothelial cells (ECs); then the ECs within a circle of 500-μm-diameter were analyzed using a custom corner method and a cell counting plugin in ImageJ.

Capabilities of Gabor-domain optical coherence microscopy for the assessment of corneal disease.

To identify the microstructural modification of the corneal layers during the course of the disease, optical technologies have been pushing the boundary of innovation to achieve cellular resolution of deep layers of the cornea. Gabor-domain optical coherence microscopy (GD-OCM), an optical coherence tomography-based technique that can achieve an isotropic of ∼2-μm resolution over a volume of 1  mm  ×  1  mm  ×  1.2  mm, was developed to investigate the microstructural modifications of corneal layers in four common corneal diseases.

Lateral eyes direct principal eyes as jumping spiders track objects.

One way of circumventing the functional tradeoffs on eye design [1,2] is to have different eyes for different tasks. For example, jumping spiders (Salticidae), known for elaborate, visually guided courtship and predatory behavior [3], view the same object simultaneously with two of their four pairs of eyes: the antero-lateral eyes (ALEs) and the principal eyes (reviewed in [2]; Figure 1A). The ALEs, with immobile lenses and retinas, wide fields of view, and hyperacute sensitivity to moving stimuli [4], are structurally distinct from the principal eyes, which have the best spatial acuity known for terrestrial invertebrates and can discern fine details of stationary objects [5].

MEMS-based handheld scanning probe with pre-shaped input signals for distortion-free images in Gabor-domain optical coherence microscopy.

High-speed scanning in optical coherence tomography (OCT) often comes with either compromises in image quality, the requirement for post-processing of the acquired images, or both. We report on distortion-free OCT volumetric imaging with a dual-axis micro-electro-mechanical system (MEMS)-based handheld imaging probe. In the context of an imaging probe with optics located between the 2D MEMS and the sample, we report in this paper on how pre-shaped open-loop input signals with tailored non-linear parts were implemented in a custom control board and, unlike the sinusoidal signals typically used for MEMS, achieved real-time distortion-free imaging without post-processing.

Optical Assessment of Soft Contact Lens Edge-Thickness.

Purpose: To assess the edge shape of soft contact lenses using Gabor-Domain Optical Coherence Microscopy (GD-OCM) with a 2-μm imaging resolution in three dimensions and to generate edge-thickness profiles at different distances from the edge tip of soft contact lenses.

Methods: A high-speed custom-designed GD-OCM system was used to produce 3D images of the edge of an experimental soft contact lens (Bausch + Lomb, Rochester, NY) in four different configurations: in air, submerged into water, submerged into saline with contrast agent, and placed onto the cornea of a porcine eyeball. An algorithm to compute the edge-thickness was developed and applied to cross-sectional images.

Real Time Gabor-Domain Optical Coherence Microscopy for 3D Imaging.

Fast, robust, nondestructive 3D imaging is needed for the characterization of microscopic tissue structures across various clinical applications. A custom microelectromechanical system (MEMS)-based 2D scanner was developed to achieve, together with a multi-level GPU architecture, 55 kHz fast-axis A-scan acquisition in a Gabor-domain optical coherence microscopy (GD-OCM) custom instrument. GD-OCM yields high-definition micrometer-class volumetric images.

Assessing microstructures of the cornea with Gabor-domain optical coherence microscopy: pathway for corneal physiology and diseases.

Gabor-domain optical coherence microscopy (GD-OCM) was applied ex vivo in the investigation of corneal cells and their surrounding microstructures with particular attention to the corneal endothelium. Experiments using fresh pig eyeballs, excised human corneal buttons from patients with Fuchs' endothelial dystrophy (FED), and healthy donor corneas were conducted. Results show in a large field of view (1  mm×1  mm) high definition images of the different cell types and their surrounding microstructures through the full corneal thickness at both the central and peripheral locations of porcine corneas.

Parallelized multi-graphics processing unit framework for high-speed Gabor-domain optical coherence microscopy.

Gabor-domain optical coherence microscopy (GD-OCM) is a volumetric high-resolution technique capable of acquiring three-dimensional (3-D) skin images with histological resolution. Real-time image processing is needed to enable GD-OCM imaging in a clinical setting. We present a parallelized and scalable multi-graphics processing unit (GPU) computing framework for real-time GD-OCM image processing.

Target flux estimation by calculating intersections between neighboring conic reflector patches.

We propose a fast algorithm to estimate the flux collected by conic reflector patches, based on the calculation of intersections between neighboring patches. The algorithm can be employed in conjunction with the supporting ellipsoids algorithm for freeform reflector design and is shown to be orders of magnitude faster and more scalable than the commonly used Monte Carlo ray tracing approach.

Direct calculation algorithm for two-dimensional reflector design.

We have developed a fast algorithm to design two-dimensional reflector surfaces that ties together the supporting paraboloids, linear programming, and numerical integration methods. The algorithm builds upon the properties of conics and is shown to be several orders of magnitude faster than the supporting paraboloids and linear programming methods. The scalability and ease of implementation of the algorithm are discussed.

Observations on the linear programming formulation of the single reflector design problem.

We implemented the linear programming approach proposed by Oliker and by Wang to solve the single reflector problem for a point source and a far-field target. The algorithm was shown to produce solutions that aim the input rays at the intersections between neighboring reflectors. This feature makes it possible to obtain the same reflector with a low number of rays - of the order of the number of targets - as with a high number of rays, greatly reducing the computation complexity of the problem.

Lightpipe device for delivery of uniform illumination for photodynamic therapy of the oral cavity.

A compact and efficient lightpipe device to deliver light to the human oral cavity for photodynamic therapy was designed and fabricated, having dimensions 6.8 mm × 6.8 mm × 46 mm.

Illumination devices for photodynamic therapy of the oral cavity.

Three compact and efficient designs are proposed to deliver an average irradiance of 50 mW/cm(2) with spatial uniformity well above 90% over a 25 mm(2) target area for photodynamic therapy of the oral cavity. The main goal is to produce uniform illumination on the target while limiting irradiation of healthy tissue, thus overcoming the need of shielding the whole oral cavity and greatly simplifying the treatment protocol. The first design proposed consists of a cylindrical diffusing fiber placed in a tailored reflector derived from the edge-ray theorem with dimensions 5.