Oregon Health & Science University

Other

University of Southern California

Yan Li

David E Huang

Maolong Tang

Yali Jia

Ou Tan

Wei Wu

Acner Camino

Huilong Duan

James T Rosenbaum

Jennifer Rose-Nussbaumer

Disclosed are systems and methods for characterizing corneal shape abnormalities. These methods may be used to differentiate corneas having subclinical keratoconus from other conditions which cause distortion of corneal shape, including warpage of the cornea due to contact lens wear. Also disclosed is classification scheme to aid diagnosis of corneal conditions and thereby guide clinical decision making regarding patient treatment. This classification scheme is based on computed properties of corneal shape, is amenable to automation, and may be implemented in an integrated system or provided in the form of software encoded on a computer-readable medium.

Diagnostic classification of corneal shape abnormalities

Described herein is an algorithm to remove decorrelation noise due to bulk motion in optical coherence tomography angiography (OCTA). OCTA B-frames are divided into segments within which the bulk motion velocity could be assumed constant. This velocity is recovered using linear regression of decorrelation versus the logarithm of reflectance in axial lines (A-lines) identified as bulk tissue by percentile analysis. The fitting parameters are used to calculate a reflectance-adjusted threshold for bulk motion decorrelation. Below this threshold, voxels are identified as non-flow tissue, and their flow values are set to zeros. Above this threshold, the voxels are identified as flow voxels and bulk motion velocity is subtracted from each using a nonlinear decorrelation-velocity relationship. Compared to the median-subtraction method, the bulk motion subtraction algorithm described herein improves angiogram signal-to-noise ratio, contrast, vessel density repeatability, and bulk motion noise cleanup, while preserving the connectivity of the vascular networks in the angiogram.

Bulk motion subtraction in optical coherence tomography angiography

Methods and systems for determining a percentage composition of aqueous cells in an anterior chamber of an eye of a subject based on cell reflectance distributions calculated from OCT image data are disclosed. In one example approach, determining a percentage composition of detected aqueous cells may comprise calculating a percentage of the detected aqueous cells which are polymorphonuclear and calculating a percentage of detected aqueous cells which are mononuclear.

Aqueous cell differentiation in anterior uveitis using optical coherence tomography

This invention discloses methods and systems for measuring corneal epithelial thickness and power, stromal thickness, subepitheila corneal power and topography. The systems and methods disclosed herein are non-invasive, non-contact and automated imaging methods which preferably makes use of Fourier-domain optical tomography. Also disclosed herein are scanning patterns and image analysis methods for utilizing and analyzing Fourier-domain optical coherence tomography images to obtain information about conical epithelial and stromal properties as well as parameters useful for evaluating the properties. The methods and systems described herein are useful as eye disease diagnostic tools and eye surgery planning tools.

Methods and systems to measure corneal epithelial thickness and power, stromal thickness, subepithelial corneal power and topography for disease diagnosis

Embodiments of OCT measurement and analysis techniques described herein enable precise 3D anterior chamber angle measurement from major, pertinent landmarks in the eye. Such techniques result in a more reliable, quantifiable angle measurement technique that is both non-invasive and non-contact in nature, thereby improving clinical practicality, while improving patient comfort and care. For example, a method is provided for in vivo imaging of an eye, including taking a plurality of optical coherence tomography (OCT) line scans of an eye to obtain a 3-dimensional (3D) radial scan pattern, the individual line scans including a plurality of axial scans, and obtaining a three-dimensional image of an anterior chamber angle of the eye from the radial scan pattern.

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Portland, OR, United States of America

Yan Li