Intraocular Lens Haptics for Capsular Bag Stability
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Solution Overview
Problem
Current intraocular lenses (IOLs) face challenges in maintaining positional stability and self-centering within the capsular bag while being small enough to fit through a sub-2.5 mm incision, which is essential for minimizing post-surgical complications such as astigmatism and ensuring effective vision correction.
Innovation Solution
The design incorporates haptics with a distal segment region and a deformation segment region, forming an angle of contact of at least 50° to 70° with the capsular bag, allowing for greater mechanical freedom and stability, and is made from hydrophobic polymeric materials with a tangent modulus of elasticity between 2 MPa to 6 MPa, enabling the lens to conform to the capsular bag without causing localized stretching or puncturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the IOL dimensions are reduced to fit through a sub-2.5 mm incision, then the ease of insertion is improved, but the strength and stability of the IOL in the eye deteriorates
Solution Approach 1:
The haptic is divided into multiple segments with different properties: a proximal segment that is more rigid for structural support and a distal segment that is more flexible for conforming to the capsular bag. This segmentation allows the IOL to maintain strength while being small enough to insert through a sub-2.5 mm incision.
Solution Approach 2:
Different portions of the haptic have different mechanical properties. The proximal portion has higher rigidity to provide structural support, while the distal portion has lower rigidity to conform to the capsular bag geometry. This local differentiation of material properties enables the IOL to achieve both stability and flexibility.
2Object-affected harmful factors
If the IOL dimensions are reduced to fit through a sub-2.5 mm incision, then the post-surgical complications are reduced, but the positional stability of the IOL in the capsular bag deteriorates
Solution Approach 1:
The haptic is designed to be dynamically adaptable to the capsular bag geometry. The distal segment can deform and conform to the curved surface of the capsular bag, creating a stable mechanical interface that maintains positional stability while allowing the IOL to be small enough to insert through a mini incision.
Solution Approach 2:
The haptic material properties are optimized with a specific range of modulus of elasticity (0.5-2.0 MPa) and water content (20-40%). These parameter changes enable the haptic to achieve the right balance of flexibility for insertion and rigidity for long-term positional stability within the capsular bag.
3Stability of the object's composition
If the haptic is made more rigid to improve stability, then the positional stability is improved, but the ability to conform to the capsular bag deteriorates
Solution Approach 1:
The haptic is segmented into a proximal segment with higher rigidity for structural support and a distal segment with lower rigidity for conforming to the capsular bag. This segmentation resolves the contradiction by assigning different mechanical properties to different functional regions of the same component.
Solution Approach 2:
The haptic is constructed as a composite structure combining materials with different mechanical properties. The composite design allows the proximal portion to provide structural stability while the distal portion conforms to the capsular bag geometry, achieving both rigidity and adaptability simultaneously.
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
This design enhances the positional stability and self-centering of the IOL within the capsular bag, reducing the risk of post-surgical complications like astigmatism and ensuring long-term vision correction by maximizing the angle of contact between the haptics and the capsular bag.
Implementation Method 1
Each of the haptics comprise a distal segment region and a deformation segment region... formed of a hydrophobic polymeric material having a tangent modulus of elasticity of 2 MPa to 6 MPa
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
An intraocular lens comprises an optic portion having a peripheral edge and at least two haptics. Each haptic is integrated with the peripheral edge of the optic portion by a corresponding haptic integration region. Also, each haptic comprises a distal segment region and a deformation segment region. The distal segment region has an outer distal length bounded by a proximate endpoint and a distal endpoint on an outer surface of the haptic, and is scribed by a distal segment angle a of 20° to 30°. The distal segment angle has a segment origin that lies within a radial segment bound by a radial distance 1.5 mm to 1.9 mm from an optic center and a segment angle ? of from 30° to 45° from a vertical axis. The vertical axis extends through the distal endpoint of at least one haptic and the optic center.