Lens Capsule Profiling with Conic and Skewed-Parabola Fits
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Solution Overview
Problem
Existing methods for obtaining a profile of the lens capsule of an eye are inadequate for accurately selecting intraocular lenses, particularly for accommodative lenses that change shape in response to external forces, due to the asymmetric and complex nature of the lens capsule's geometry.
Innovation Solution
A system and method using a controller with a processor and memory to transform imaging data of the lens capsule into an adjusted frame of reference, fitting it to conic surfaces and skewed parabolas, and solving constraints to determine fitting parameters, enabling precise representation of the lens capsule's profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional imaging methods are used to obtain lens capsule profile, then the process is simple, but the measurement precision is insufficient for asymmetric and complex geometry
Solution Approach 1:
The lens capsule profile is segmented into distinct geometric regions: central anterior surface, central posterior surface, equatorial anterior surface, and equatorial posterior surface. Each region is fitted with appropriate mathematical models (conic surfaces for central regions, skewed parabolas for equatorial regions), allowing precise representation of the asymmetric geometry while managing computational complexity through regional decomposition.
Solution Approach 2:
The patent transforms the coordinate system to an adjusted frame of reference with specific orientation and origin positioning. This parameter transformation simplifies the mathematical representation by aligning the coordinate system with the lens capsule's principal axes, enabling more accurate fitting of asymmetric surfaces while reducing the complexity of the fitting algorithms.
2Measurement precision
If detailed imaging data processing is performed to capture asymmetric geometry, then the profile accuracy improves, but the computation time increases
Solution Approach 1:
By dividing the lens capsule profile into four distinct surfaces with specific mathematical models, the patent captures asymmetric geometry efficiently. Each segment is fitted independently with appropriate equations (conic for central, skewed parabola for equatorial), reducing the overall computational burden compared to fitting a single complex model to the entire asymmetric structure.
Solution Approach 2:
The patent fits imaging data to surfaces in a predefined central region rather than attempting to fit the entire lens capsule profile. This partial action approach focuses computational resources on the most critical central region where precision is most needed for intraocular lens selection, while still capturing the essential asymmetric geometry.
3Measurement precision
If multiple fitting parameters are determined to represent the profile, then the representation accuracy increases, but the device complexity increases
Solution Approach 1:
The profile representation is segmented into four surfaces, each with its own fitting parameters. The central anterior and posterior surfaces use conic surface parameters, while the equatorial surfaces use skewed parabola parameters. This segmentation allows determination of multiple parameters in a structured manner, improving representation accuracy while managing complexity through systematic organization of parameter determination.
Solution Approach 2:
The patent determines fitting parameters including conic coefficients (K, Q, R) for central surfaces and parabola coefficients for equatorial surfaces, along with transition coordinates and vertex positions. These parameter transformations from raw imaging data to geometric model parameters enable accurate profile representation while providing a standardized framework for parameter determination that reduces overall system complexity.
Data Source
AI summary
A system includes a controller with at least one processor and at least one non-transitory, tangible memory on which instructions are recorded for executing a method for obtaining a profile of a lens capsule of an eye. The profile is represented by respective central surfaces and respective equatorial surfaces separated at respective transition points. The controller is configured to obtain imaging data for a portion of the lens capsule visible through a pupil of the eye. The imaging data is transformed to an adjusted frame of reference and fitted to the respective central surfaces in a predefined central region of the lens capsule. The profile is obtained based on a set of fitting parameters for the respective central and equatorial surfaces. The respective central surfaces and respective equatorial surfaces may be represented as elliptical cones and skewed parabolas, respectively.