Multipass VIPA Etalon for Corneal Biomechanical Mapping
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Solution Overview
Problem
Current methods for diagnosing and treating eye disorders, such as keratoconus and post-LASIK ectasia, lack precision in determining biomechanical properties of the cornea, which is crucial for planning and assessing cross-linking treatments.
Innovation Solution
Employing Brillouin scattering to determine viscoelastic properties of corneal tissue using a system that includes a light source, confocal microscopy, and a spectrometer to analyze the Brillouin frequency shift, generating a three-dimensional profile of the cornea for accurate treatment planning and monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Brillouin scattering is employed to determine biomechanical properties of corneal tissue, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The optical system is segmented into distinct functional modules: a light source module, a VIPA spectrometer module with specific optical cavity configuration, and a detection module. This segmentation allows each component to be optimized independently for its specific function while maintaining overall system precision for Brillouin scattering measurements.
Solution Approach 2:
The VIPA etalon acts as an intermediary optical element that mediates between the incident light and the detector. It creates multiple virtual images of the entrance window through successive reflections, enabling high-resolution spectral analysis of Brillouin scattering without requiring complex direct spectroscopic instrumentation.
2Measurement precision
If multiple passes through the optical cavity are implemented, then spectral resolution is improved, but loss of energy increases
Solution Approach 1:
The VIPA etalon creates multiple virtual copies (images) of the entrance window at different optical path lengths. Each virtual image corresponds to a different number of passes through the optical cavity, allowing the system to accumulate spectral information from multiple passes while maintaining a simple physical structure and minimizing energy loss through efficient optical path management.
Solution Approach 2:
The system changes the optical path length parameter by varying the angle of incidence of light on the VIPA etalon. This allows control over the number of passes light makes through the optical cavity, enabling optimization between spectral resolution and energy conservation by adjusting the incidence angle to achieve the desired number of reflections.
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 allows for precise identification of corneal weakness and real-time monitoring of cross-linking treatments, enhancing the effectiveness and stability of corneal treatments by providing detailed biomechanical mapping.
Implementation Method 1
The optical device includes a reflective first surface and a partially reflective/transmissible second surface parallel to the first surface. The light rays are reflected between the first and second surfaces multiple times and to traverse the optical cavity
Implementation Method 2
A portion of light from the light rays is transmitted through the second surface with each reflection at the second surface. The transmitted portions of light generate an interference pattern that provides spectral information for the light
Implementation Method 3
the systems and methods may employ the principle of Brillouin scattering to determine biomechanical properties of the eye. In particular, the systems and methods may evaluate Brillouin shift to determine viscoelastic and other properties of corneal tissue
Data Source
AI summary
An example system determines biomechanical properties of eye tissue. The system includes a confocal microscopy system configured to scan the incident light across a plurality of cross-sections of the tissue. The incident light is reflected by the plurality of cross-sections of tissue as scattered light. The system includes a spectrometer to receive the scattered light and provide spectral information for the scattered light. The system includes processor(s) to determine a Brillouin frequency shift from the spectral information and to generate a three-dimensional profile of the corneal tissue according to the Brillouin frequency shift. The three-dimensional profile provides an indicator of one or more biomechanical properties of the tissue. The spectrometer includes a multipass optical device that generates an interference pattern from the scattered light. The interference pattern provides the spectral information for the scattered light. The spectrometer includes a camera to detect the interference pattern from the optical device.