Focus-Tunable Ocular Wavefront Imaging for Precise IOL Calculation
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Solution Overview
Problem
Current wavefront aberrometry systems lack biometric and anatomical information, limiting the accuracy of intra-operative intra-ocular lens (IOL) power calculation and surgical outcomes, while existing optical coherence tomography (OCT) methods suffer from calibration issues and slow imaging speed.
Innovation Solution
An optical apparatus combining wavelength tunable laser light or broad band partially coherent light sources with focus tunable optics and digital adaptive optics (DAO) algorithms to calculate wavefront error at different eye planes, integrating OCT imaging for biometric data and DAO algorithms for precise IOL power calculation and alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wavefront aberrometry is used for vision correction, then optical properties of the eye can be measured, but biometric and anatomical information is lacking
Solution Approach 1:
The patent combines wavefront aberrometry and OCT imaging into a single integrated system. The OCT component provides biometric and anatomical information (axial length, corneal curvature, anterior chamber depth) while the wavefront aberrometry measures optical properties. By merging these two measurement modalities, the system eliminates information loss and provides comprehensive data for IOL power calculation.
2Measurement precision
If Shack-Hartmann sensor is used, then wavefront measurement is available, but dynamic range is limited
Solution Approach 1:
The patent employs a focus-tunable lens in the OCT path that can dynamically adjust its focal length. This dynamic focusing capability allows the system to maintain optimal focus across a wide range of diopter values, significantly expanding the dynamic range from the limited range of fixed-focus Shack-Hartmann sensors to accommodate aphakic and pseudophakic eyes with high hyperopia.
3Loss of information
If OCT imaging is used, then anatomical and biometric information is provided, but imaging speed is slow
Solution Approach 1:
The patent uses a swept-source laser that rapidly sweeps through a range of wavelengths in a periodic manner. This swept-source approach enables high-speed OCT imaging by acquiring depth information for the entire eye in just a few milliseconds, dramatically improving imaging speed compared to traditional spectral-domain OCT while maintaining comprehensive anatomical and biometric information acquisition.
4Ease of operation
If generalized regression formula is used for IOL power calculation, then calculation is simple, but accuracy is limited
Solution Approach 1:
The patent implements a feedback mechanism where the OCT-derived biometric parameters (axial length, corneal curvature, anterior chamber depth) and wavefront aberration measurements are fed into an optimized IOL power calculation algorithm. This feedback loop allows the system to continuously refine the IOL power calculation based on actual measured parameters, significantly improving accuracy over static regression formulas.
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
Provides accurate wavefront error calculations over a wide dynamic range, enabling precise IOL power selection and alignment, improving surgical outcomes by combining OCT imaging with DAO techniques.
Implementation Method 1
a source of wavelength tunable laser light (100) or a broad band partially coherent light source (1001)
Implementation Method 2
a first beam splitter (111, 1011), means for directing the illumination light via the first beam splitter (111, 1011) as a light spot to a sample
Implementation Method 3
a focus tunable optics (112, 1012) receiving the image of the light spot from the sample after being transmitted through the first beam splitter (111, 1011) and focusing the image to a detection plane
Implementation Method 4
wherein a photodetector unit is adapted for receiving the recombined light from the sample arm (110, 1010) and the reference arm (120, 1020)
Implementation Method 5
the sample arm (110, 1010) comprises a separate illumination channel configured to inject light via a mirror (116, 1003) and the first beam splitter (111, 1011) to the sample
Data Source
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AI summary
The disclosure provides an optical apparatus, comprising: a source of wavelength tunable laser light or a broad band partially coherent light source, a first beam splitter receiving the light and directing a part of the light to a sample arm as illumination light and another part of the light to a reference arm as reference light, the sample arm comprising: means for directing the illumination light via a first beam splitter as a light spot to a sample, wherein an image of the light spot is reflected from the sample, a focus tunable optics receiving the image of the light spot from the sample after being transmitted through the first beam splitter and focusing the image to a detection plane, wherein a photodetector unit is adapted for receiving the recombined light from the sample arm and the reference arm. Preferably, a computing unit is connected to the photodetector unit, wherein the computing unit is configured to digitize the signal and use digital techniques to calculate wavefront error at different planes, e.g. in the human eye.