Corneal Surface Characterization via Polarized Light Segmentation
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Solution Overview
Problem
Current methods for determining corneal thickness and characterizing the back surface of the cornea, such as optical coherence topography and Scheimpflug photography, lack effective alternatives for precise measurement and characterization, particularly in scenarios like LASIK treatment planning.
Innovation Solution
A system comprising a light pattern generator, detector, processor, polarization element, and beamsplitter that uses polarized light to differentiate between reflections from the front and back surfaces of the cornea by altering polarization, allowing for the characterization and measurement of corneal thickness through image processing and analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods (optical coherence topography or Scheimpflug photography) are used to measure corneal thickness and characterize back surface, then measurement capability is provided, but measurement precision and reliability are insufficient
Solution Approach 1:
The patent segments the reflected light into two distinct polarization components: one reflecting from the front corneal surface and another from the back corneal surface. By using polarization-sensitive detection, the system separates these overlapping signals spatially and polarization-wise, enabling independent characterization of each surface and improving measurement precision of corneal thickness.
Solution Approach 2:
The patent introduces polarization state as an intermediary parameter to differentiate between front and back surface reflections. By encoding surface information into polarization states and using polarization-sensitive detectors, the system acts as a mediator to separate and identify signals from different corneal surfaces, thereby improving reliability of back surface characterization.
2Measurement precision
If polarized light is used to differentiate front and back surface reflections, then signal isolation from back surface is improved, but device complexity increases
Solution Approach 1:
The patent employs a polarization-sensitive camera that simultaneously captures both polarization components and spatial information in a single measurement. This multi-functional detector eliminates the need for complex mechanical scanning systems or multiple separate measurement devices, achieving signal isolation while maintaining relatively simple device architecture.
Solution Approach 2:
The system creates polarization-encoded optical copies of the corneal surfaces, where each surface's reflection is tagged with a distinct polarization signature. This optical copying approach allows simultaneous detection of multiple surfaces without physical contact or mechanical movement, simplifying the overall system while improving measurement capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the accuracy of corneal surface characterization and thickness measurement by isolating and amplifying the signal from the back surface, reducing interference from the front surface reflections, thereby improving precision and reliability.
Implementation Method 1
rotating a polarization element of the system to a first polarization angle that is aligned with a polarization of light reflected by the anterior surface of the cornea
Implementation Method 2
light reflected by the anterior surface of the cornea
Data Source
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AI summary
A system includes a light pattern generator having light spots for illuminating front and back surfaces of a cornea with polarized light; one or more detectors for receiving one or more of first spot images from light reflected off the front surface, and second spot images from light reflected off the back surface, the light reflected off the front surface having a first polarization and the light reflected off the back surface having a second polarization; a polarization element in an optical path between the back surface and the one or more detectors, the polarization element being configured to attenuate an intensity of the light reflected off the front surface by an amount greater than an amount by which it attenuates the light reflected off the back surface; and a processor for determining a geometric characteristic of the cornea using at least the second plurality of spot images.