Intraocular Lens Shape Factor Optimization for Aberration Control
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Solution Overview
Problem
Intraocular lenses (IOLs) implanted during cataract surgery often experience degraded optical performance due to misalignment and inherent eye aberrations, leading to suboptimal vision correction.
Innovation Solution
Designing ophthalmic lenses with an optic having an anterior and posterior surface, featuring a shape factor range of -0.5 to 4, and an aspheric base profile with a conic constant between -73 and -27, optimized for specific ocular biometric parameters to minimize aberrations and enhance optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional spherical IOLs are used, then manufacturing is simpler, but optical performance degrades due to aberrations from misalignment and eye imperfections
Solution Approach 1:
The patent applies aspheric curvature to the IOL surfaces, replacing traditional spherical designs. The aspheric surfaces are defined by conic sections with specific conic constants (k values) that optimize optical performance. This curvature modification reduces spherical aberration and improves image quality while maintaining manufacturing feasibility through established aspheric molding techniques.
Solution Approach 2:
The patent systematically varies key geometric parameters including shape factor (SF), conic constant (k), and surface curvatures to optimize optical performance. Different parameter combinations are evaluated for their ability to reduce aberrations from tilt and decentration. This parametric optimization allows tailoring the lens design to specific ocular conditions while maintaining a manageable design space.
2Reliability
If IOLs with optimized aspheric profiles are designed, then aberrations from tilt and decentration are reduced, but manufacturing precision requirements increase
Solution Approach 1:
The aspheric surfaces are defined by mathematically precise conic section equations with specific conic constants. These standardized mathematical forms enable accurate manufacturing through computer-controlled molding while providing robust aberration correction. The conic constant parameterization allows precise control of surface shape within manufacturing tolerances.
Solution Approach 2:
The aspheric design inherently compensates for expected misalignments (tilt and decentration) that occur during implantation. By pre-designing the surface geometry to counteract these anticipated errors, the lens maintains optimal optical performance even when not perfectly aligned, reducing the impact of manufacturing and surgical variations.
3Reliability
If a single IOL design is used for all patients, then device complexity is minimized, but optical performance varies across different ocular biometrics
Solution Approach 1:
The patent establishes systematic relationships between patient-specific ocular biometrics (corneal radius, axial length, anterior chamber depth) and optimal IOL geometric parameters (shape factor, conic constant). This parametric design approach allows selection or customization of lens parameters based on individual eye measurements, optimizing performance across diverse patient populations while maintaining a family of related designs rather than completely different devices.
Solution Approach 2:
The aspheric IOL design framework provides a universal solution that can accommodate various ocular biometrics through parameter adjustment rather than requiring entirely different lens designs. The same fundamental aspheric geometry with modified parameters can serve multiple patient types, balancing customization needs with manufacturing efficiency and design standardization.
Data Source
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Figure 3
Figure 4A~4B
AI summary
The present invention provides an ophthalmic lens (10,22) including an intraocular lens (TOL) comprising an optic (12) having an anterior surface (14,26) and a posterior surface (16,24), said optic exhibiting a shape factor, defined as a ratio of the sum of the anterior and posterior curvatures to the difference of such curvatures, in a range of - 0.5 to 4. The optic is formed entirely from at least one solid biocompatible material.