Auxetic Polymer Foam Haptics for Lighter, Flexible Intraocular Lenses
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Solution Overview
Problem
Existing intraocular lenses (IOLs) are heavy and cumbersome, making surgical implantation difficult and uncomfortable for patients, and they lack materials that provide optimal biocompatibility, flexibility, and refractive properties.
Innovation Solution
Incorporating a negative Poisson's ratio (NPR) polymer foam material for the haptics and optionally the circumferential optic of the IOL, which provides enhanced flexibility and biocompatibility, along with a transparent material with a positive Poisson's ratio for the optical zone, allowing for a lighter and easier implantation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If conventional materials are used for intraocular lenses, then structural strength is maintained, but weight increases making implantation difficult and uncomfortable
Solution Approach 1:
The patent employs polymer foam materials with controlled cellular structures (characteristic dimensions of 0.1-3 μm) to create intraocular lenses with reduced density and weight. The porous foam structure allows significant weight reduction while maintaining structural integrity through the cellular architecture, directly resolving the contradiction between weight and strength
Solution Approach 2:
The patent uses composite construction with an inner region made of traditional optical materials (acrylic, silicone, or hydrogel) and an outer region made of NPR polymer foam material. This composite approach allows the optical zone to maintain necessary strength and optical properties while the foam haptics reduce overall weight, enabling easier implantation
2Ease of operation
If traditional materials are used for haptics, then structural stability is achieved, but flexibility and biocompatibility are insufficient
Solution Approach 1:
The patent changes the material parameters by introducing polymer foam with negative Poisson's ratio properties, which exhibits enhanced flexibility and elasticity compared to traditional rigid materials. The controlled cellular structure and characteristic dimensions (0.1-3 μm) allow tuning of mechanical properties to achieve optimal flexibility while maintaining stability
Solution Approach 2:
The patent applies different material properties to different regions: the inner optical region uses traditional materials for stability, while the outer haptic region uses NPR foam material for enhanced flexibility and biocompatibility. This local differentiation allows each region to optimize its performance for its specific function
3Reliability
If single-material construction is used, then manufacturing is simplified, but optimal refractive properties and biocompatibility cannot be achieved simultaneously
Solution Approach 1:
The patent implements a two-region construction where the inner region is optimized for optical properties (refractive index) and the outer region is optimized for biocompatibility and mechanical properties. This local quality differentiation allows each region to use materials best suited for its specific function, achieving optimal overall performance
Solution Approach 2:
The patent uses composite construction combining different material classes (acrylic/silicone/hydrogel for optical zone, polymer foam for haptic zone) to achieve properties that neither material could provide alone. The manufacturing process integrates these materials into a single cohesive lens structure, balancing complexity with performance
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
The use of NPR materials results in IOLs that are lighter, more comfortable, and easier to implant, while maintaining optimal biocompatibility and refractive properties, improving surgical outcomes.
Implementation Method 1
one or more haptics formed of a polymer foam material having a negative Poisson's ratio (NPR)
Implementation Method 2
The polymer foam material of the lens element is composed of a cellular structure having a characteristic dimension of between 0.1 μm and 3 μm
Implementation Method 3
The lens includes an inner region having a first index of refraction and an outer region disposed circumferentially surrounding the inner region, the outer region having a second index of refraction different from the first index of refraction
Data Source
AI summary
An intraocular lens includes a substantially circular lens element formed of a transparent material and one or more haptics extending outwardly from an outer edge of the lens element. The one or more haptics are formed of a polymer foam material having a negative Poisson's ratio (NPR) and are configured to couple the intraocular lens to an eye of a patient. The lens includes an inner region having a first index of refraction and an outer region disposed circumferentially surrounding the inner region, the outer region having a second index of refraction different from the first index of refraction.