Full Crystalline Lens Shape Estimation Using OCT for IOL Positioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical imaging methods for in-vivo crystalline lens measurements fail to accurately estimate critical parameters such as equatorial plane position, volume, surface area, and diameter due to limitations in capturing non-visible lens portions, leading to errors in intraocular lens (IOL) position estimation and power calculation.
Innovation Solution
A method using optical imaging techniques like OCT to measure visible lens portions, combined with ex-vivo data to estimate non-visible portions, employing a geometric model to displace points and apply weight coefficients for accurate full shape estimation, enabling precise IOL position prediction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical imaging techniques are used to measure the crystalline lens in-vivo, then measurement speed and resolution are improved, but the ability to capture the full lens shape including non-visible portions deteriorates
Solution Approach 1:
The lens shape estimation is segmented into two parts: visible portions measured directly by optical imaging and non-visible portions estimated through mathematical extrapolation. This segmentation allows each part to be handled with the most appropriate method while maintaining overall measurement precision.
Solution Approach 2:
A geometric model acts as an intermediary between the visible measurements and the complete lens shape. The model uses the measured visible portions as input and generates estimates of non-visible portions, effectively bridging the information gap created by the imaging technique's limitations.
2Productivity
If intersection approaches are used to estimate lens parameters from optical imaging data, then the method is simple and fast, but estimation accuracy deteriorates due to overestimation of volume, surface area, and diameter
Solution Approach 1:
The method performs preliminary actions by first measuring the visible portions of the lens with high precision using optical imaging, then uses these accurate measurements as a foundation for estimating non-visible portions. This preliminary high-precision measurement prevents the overestimation errors that occur when starting with incomplete data.
Solution Approach 2:
The approach changes the estimation parameters by using multiple measured parameters (anterior radius, posterior radius, thickness, visible surface area) to derive the non-visible parameters through mathematical relationships, rather than using a single intersection point method that leads to systematic overestimation.
3Loss of information
If MRI is used to capture the entire lens shape, then complete lens geometry is obtained, but acquisition time increases significantly and resolution decreases
Solution Approach 1:
The method extracts only the necessary information (visible portions of the lens) using fast optical imaging techniques, then derives the complete geometry through mathematical estimation. This extraction approach avoids the need for slow, comprehensive MRI scanning while still obtaining complete lens geometry.
Solution Approach 2:
Instead of directly imaging the entire lens with MRI, the method creates a computational copy of the non-visible lens portions based on the visible measurements. This copying process reconstructs the complete lens geometry without requiring physical access to all portions through slow imaging.
4Device complexity
If constant EPP values are used in IOL position estimation, then the calculation is simplified, but accuracy deteriorates because EPP is subject-dependent
Solution Approach 1:
The method transitions from a static, constant EPP value to a dynamic, subject-dependent EPP value that is calculated individually for each patient based on their specific lens geometry measurements. This dynamic approach maintains calculation simplicity while improving accuracy by adapting to individual variations.
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 a non-invasive, accurate estimation of the full crystalline lens shape, improving IOL power selection and surgical outcomes by reducing estimation errors, facilitating custom IOL design and presbyopia treatments.
Implementation Method 1
measurements taken by optical imaging techniques
Implementation Method 2
Optical Coherence Tomography (OCT)
Data Source
AI summary
The present invention relates to a method and a device for estimating a full shape of a lens of an eye from measurements of the lens taken in-vivo by optical imaging techniques, the measurements comprising visible portions of the lens, the method comprises defining non-visible portions of the lens parting from the in-vivo measurements and using a geometrical model of a lens previously built from ex-vivo measurements. The full shape parameters of the crystalline lens can be estimated in the present invention from optical imaging techniques to improve the estimation of the IOL position and thus the IOL power selection.