Flexible Intraocular Lens Haptics for Smaller-Incision Implantation
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Solution Overview
Problem
Existing intraocular lenses (IOLs) require large incisions for implantation due to the significant difference in mechanical properties between the optic and haptics, leading to invasive surgery and potential complications such as surgically induced astigmatism and instability during implantation.
Innovation Solution
The use of a haptic with a Young's modulus greater than the optic but less than 1.8 GPa, allowing for a thinner and more flexible design that can be implanted through smaller incisions, using materials like silicone, urethane, and acrylic with tailored stoichiometry to achieve desired stiffness and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the haptics are made significantly thicker to provide sufficient mechanical strength, then the mechanical strength is improved, but the incision size required for implantation increases
Solution Approach 1:
The patent changes the material parameter (Young's modulus) of the haptics from traditional stiff materials like PMMA to a flexible material with a Young's modulus between 0.1-1.8 GPa. This parameter change allows the haptics to achieve sufficient mechanical strength through optimized material properties rather than increased thickness, enabling implantation through smaller incisions (2.2-3.0 mm) while maintaining the required structural strength to hold the optic in place
Solution Approach 2:
The patent employs composite material construction where the haptics are made from a flexible optical material that is different from the optic material. This composite approach allows each component to be optimized independently - the optic for optical performance and the haptics for mechanical strength with reduced thickness - resolving the contradiction between strength requirements and incision size
2Strength
If the haptics are made from a stiff material like PMMA, then the mechanical strength is improved, but the flexibility for small incision implantation deteriorates
Solution Approach 1:
The patent fundamentally changes the material parameter by selecting a flexible material with Young's modulus of 0.1-1.8 GPa for the haptics, replacing traditional stiff PMMA materials. This parameter change enables the haptics to be sufficiently flexible for implantation through small incisions while maintaining adequate mechanical strength through material property optimization rather than geometric thickening
3Ease of manufacture
If the haptics and optic are made from the same flexible material, then the manufacturing simplicity is improved, but the mechanical strength of haptics deteriorates
Solution Approach 1:
The patent applies composite material construction by using a flexible optical material for both the optic and haptics, but with different formulations or processing to achieve different Young's moduli. The haptics are specifically formulated to have a Young's modulus of 0.1-1.8 GPa, providing sufficient mechanical strength, while the optic uses a different formulation optimized for optical performance. This composite approach maintains manufacturing simplicity through a unified material system while achieving the required strength differentials
4Ease of operation
If a large incision is used for IOL implantation, then the ease of implantation is improved, but the invasiveness and surgical complications increase
Solution Approach 1:
The patent changes the material parameter (Young's modulus) of the haptics to a flexible range (0.1-1.8 GPa), which enables the haptics to be sufficiently thin and flexible for implantation through smaller incisions (2.2-3.0 mm). This parameter change reduces surgical invasiveness and associated complications while maintaining the mechanical strength needed for proper IOL function, thus resolving the contradiction between ease of implantation and surgical harm
Data Source
Figure 1A~1B
Figure 2~3
Figure 4A~4B
AI summary
A method and system provide an ophthalmic device (100) including an optic (110) and a haptic (120). The optic includes at least one optical material having a first Young's modulus. The haptic is coupled with the optic. The haptic includes at least a second Young's modulus greater than the first Young's modulus and less than 1.8 GPa. Thus, the haptic is stiffer than the optic, but more flexible than a material such as polymethyl metacrylate (PMMA).