Toric Intraocular Lens with Rectangular Protrusions for Rotational Stability
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Solution Overview
Problem
Current intraocular lenses (IOLs) face challenges in effectively correcting astigmatism and presbyopia due to rotational instability and misalignment, leading to residual astigmatism and vision degradation, especially when combined with other eye conditions.
Innovation Solution
An intraocular lens with a customized cylindrical profile and protrusions forming a rectangular shape to lock into position, preventing rotation and ensuring precise alignment with the astigmatism of the eye, combined with a diffractive pattern for multifocal vision and a toric profile to correct astigmatism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional intraocular lens is used to correct astigmatism, then the lens can be implanted to provide refractive correction, but the lens rotates after insertion into the capsular bag, causing misalignment and residual astigmatism
Solution Approach 1:
The haptics are designed with asymmetric features including a first haptic with a different profile than a second haptic, and the presence of a leading edge and trailing edge on the optical element. This asymmetry prevents the lens from rotating to incorrect orientations, as the asymmetric haptics engage with the capsular bag in a orientation-specific manner, ensuring the optical element maintains its intended alignment with the eye's astigmatic meridians.
Solution Approach 2:
The lens is pre-aligned during manufacturing with the astigmatic correction oriented correctly. The asymmetric haptic design incorporates pre-determined engagement features that automatically orient the optical element in the correct position upon insertion into the capsular bag, eliminating the need for post-insertion alignment adjustments and preventing subsequent rotation.
2Stability of the object's composition
If the lens is made with asymmetric haptics to prevent rotation, then rotational stability is improved, but the device complexity increases
Solution Approach 1:
Rather than making the entire lens complex, the asymmetric features are applied locally only to the haptics. The optical element itself remains relatively simple, with the complexity concentrated in the haptic structures that engage with the capsular bag. This localized approach to asymmetry provides rotational stability without requiring the entire device to be overly complex.
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 solution provides rotational stability and precise alignment, effectively correcting astigmatism and presbyopia, reducing residual astigmatism and improving vision quality by ensuring the lens remains fixed in place, even with eye growth or capsular bag changes.
Implementation Method 1
The intraocular lens comprises a diffractive pattern
Implementation Method 2
The lens body customized for astigmatism in a particular eye
Data Source
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AI summary
An intraocular lens comprises a lens body customized for astigmatism in a particular eye. For the customization to work, the astigmatism in the lens has to be aligned with astigmatism in the eye. Thus the intraocular lens comprises four protrusions arranged outwardly around the lens body to form the four corners of a substantially rectangular profile. The profile locks the intraocular lens into a position of rotational stability when inserted into a capsular bag, thus preventing rotation of the intraocular lens, which would otherwise tend to occur both immediately after insertion into the capsular bag and later on during growth, shrinkage or other change to the capsular bag. The Intraocular lens may additionally be customized for other eye conditions and a multi-focal embodiment is also disclosed.