Methods and systems for quantitative ocular surface diagnostics

Inventors

Zavislan, James M. • Zhang, Aizhong

Assignees

University of Rochester

Abstract

The present disclosure provides systems and methods for characterizing thin films, such as, for example, diagnosis of dry eye syndrome, thin-film optical metrology testing, etc. The present disclosure may be embodied as a tearscope, which is sometimes referred to herein as a Macroscopic Imaging Ellipsometer (MIE) because it may be considered to be an imaging ellipsometer with, for example, a field-of-view on the order of tens of millimeters or more (i.e., macroscopic), compared with conventional imaging ellipsometers, which usually employ microscope objectives and have fields-of-view of up to several hundred microns.

Core Innovation

An apparatus measures thermal impulse response of a tear film of an eye using an infrared source configured to emit infrared energy and heat the tear film according to a known spatial pattern, an infrared imager configured to receive infrared energy emitted by the eye, and a controller configured to pulse the infrared source and obtain infrared images of at least a portion of the eye at a predetermined time after the pulse. The controller analyzes a thermal decay of the infrared signal resulting from the spatial pattern of the heated tear film to determine a thermal impulse response of the tear film.

Based on the thermal impulse response, the controller determines a thickness of the tear film of the eye. In embodiments, the known spatial pattern is implemented using a mask, the optical assembly focuses the spatial pattern of infrared energy onto the tear film, and the spatial pattern is configured as a slit or a dot array spot-line pattern.

The document also discloses multimodal integration with an ocular-surface tear film imaging ellipsometer. A macroscopic imaging ellipsometry/ellipsometer-based tearscope images the tear-film thin film with multiple polarization states and uses phantom calibration to normalize illuminator radiance for effective reflectance imaging ellipsometry and/or absolute reflectance imaging ellipsometry, including lookup-table inversion to estimate tear-lipid layer thickness and refractive index.

Claims Coverage

The partial content provides one independent claim covering thermal impulse response measurement and tear film thickness determination from patterned infrared heating and thermal decay analysis. Dependent claims refine the spatial pattern, infrared emission characteristics, and multi-band thermal imaging.

Across the provided claims, tear film thickness is determined by deriving a thermal impulse response from thermal decay of an infrared signal produced by a known spatial heating pattern. The dependent claims further specify the spatial pattern implementation, optical focusing, infrared emission bands, and multi-band thermal imaging used for thickness estimation.

Stated Advantages

Documented Applications