Asymmetric Intraocular Lens Haptics for Stable Capsular Fixation
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Solution Overview
Problem
Existing intraocular lenses (IOLs) face issues with secure fixation in capsular bags of varying sizes, leading to deformation, rotation, and increased risk of secondary cataracts due to uneven pressure distribution and stress on the optical body.
Innovation Solution
An intraocular lens design with two haptics, each having multiple arms, where the arms are arranged to ensure secure fixation by distributing restoring forces evenly and reducing stress peaks, thereby minimizing deformation and rotation of the optical body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform haptic size is used in traditional IOLs, then the manufacturing is simple, but the fixation is insecure in large capsular bags and causes deformation in small capsular bags
Solution Approach 1:
The haptic is divided into multiple arms (first arm and second arm) with different lengths extending from the optical body. The first arm has a first distance from the optical axis while the second arm has a second distance, creating asymmetric segments that can adapt to varying capsular bag sizes and provide secure fixation across different eye types.
Solution Approach 2:
Different arms of the haptic are designed with different local properties - the first arm extends to a first distance from the optical axis while the second arm extends to a second distance. This local differentiation allows each arm to optimally engage with the capsular bag wall at different radial positions, providing reliable fixation whether the capsular bag is large or small.
2Volume of stationary object
If the capsular bag is large, then more space is available for the optical body, but the haptic exerts low pressure resulting in optical body shifting or rotation
Solution Approach 1:
The haptic design transitions from a single radial dimension to multiple radial dimensions by having arms extend to different distances from the optical axis. The first arm reaches a first distance while the second arm reaches a second distance, creating a multi-dimensional engagement pattern that increases contact area and frictional force, preventing optical body shifting or rotation even in large capsular bags.
3Volume of stationary object
If the capsular bag is small, then the optical body is well-contained, but the haptic causes deformation such as ovalization increasing secondary cataract risk
Solution Approach 1:
The haptic is segmented into multiple arms with different lengths and orientations. The first arm extends to a first distance from the optical axis while the second arm extends to a second distance. This segmentation distributes the restraining force across multiple contact points on the capsular bag wall, preventing concentration of stress that would cause ovalization or folding in small capsular bags.
Solution Approach 2:
The haptic employs asymmetric arm lengths where the first arm has a different distance from the optical axis compared to the second arm. This asymmetric configuration allows the arms to engage with the capsular bag at different radial positions, distributing pressure evenly and preventing the uniform compression that leads to ovalization and folding in small capsular bags.
4Device complexity
If a single arm haptic is used, then the structure is simple, but the restoring force is not evenly distributed causing stress peaks on the optical body
Solution Approach 1:
The haptic is divided into multiple arms (first arm and second arm) with different lengths extending from the optical body. The first arm extends to a first distance from the optical axis while the second arm extends to a second distance. This segmentation distributes the restoring force across multiple attachment points, preventing stress concentration at a single point on the optical body.
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 dual-haptic design effectively secures the optical body within the capsular bag, reducing the likelihood of secondary cataract and rotation of the optical body, preventing it from pivoting around its optical axis.
Implementation Method 1
the first arm has a first relaxed state in which the first arm is free from mechanical stress... the second arm has a second relaxed state in which the second arm is free from mechanical stress
Data Source
Figure 1
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AI summary
The invention relates to an intraocular lens (1) with an optical body (2) which has an optical axis (3) and a circumferential direction (4) in relation to the optical axis (3), with a first haptic (11) which has a first arm (13), a first longitudinal end (51) of the first arm fastened to the optical body, a second longitudinal end (52) of the first arm and a first relaxation state in which the first arm is free of mechanical stress, and has a second arm (14), a first longitudinal end (51) of the second arm fastened to the optical body, a second longitudinal end (52) of the second arm and a second relaxation state in which the second arm is free of mechanical stress, wherein the first arm has a first point (21) which, in the first relaxation state, has a first distance from the optical axis and, in the first relaxation state, is the point on the first arm at the longest distance from the optical axis, wherein the second arm has a second point (22) which, in the second relaxation state, has a second distance from the optical axis and, in the second relaxation state, is the point on the second arm at the longest distance from the optical axis, wherein the first distance is longer than the second distance, and with a second haptic (12), which is fastened to the optical body and is arranged facing away from the first haptic.