Bimodulus Contact Lens with Radially Asymmetric Rigidity
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Solution Overview
Problem
Current multifocal contact lenses for presbyopia correction often fail to adequately address astigmatic errors, leading to image degradation and reduced performance, as they require precise fitting and orientation to correct refractive errors effectively.
Innovation Solution
Bimodulus soft contact lenses with a deformable inner optic portion of higher rigidity than the outer peripheral portion, designed to conform to the cornea and create a lenticular volume that corrects both presbyopia and astigmatic errors, allowing for tear fluid to fill and maintain a radially symmetric spherical surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If soft multifocal contact lenses are used for presbyopia correction, then comfort and oxygen permeability are improved, but astigmatic error correction is insufficient leading to image degradation
Solution Approach 1:
The lens employs different rigidity values in different regions: the central optic portion has a higher rigidity (1E8 to 1E10 MPa-μm³) to maintain shape and correct astigmatism, while the peripheral portion has a lower rigidity (1E6 to 1E8 MPa-μm³) for comfort and conformability to the cornea. This local differentiation allows the soft lens to provide both comfort and astigmatic correction.
2Reliability
If rigid gas permeable lenses are used to correct astigmatism, then astigmatic error correction is improved, but comfort and adaptability are reduced
Solution Approach 1:
The lens employs different rigidity values in different regions: the central optic portion has a higher rigidity (1E8 to 1E10 MPa-μm³) to maintain shape and correct astigmatism, while the peripheral portion has a lower rigidity (1E6 to 1E8 MPa-μm³) for comfort and conformability to the cornea. This local differentiation allows the soft lens to provide both comfort and astigmatic correction.
3Reliability
If cylindrical corrective components are added to lenses for astigmatism, then astigmatic error correction is improved, but device complexity and inventory requirements increase
Solution Approach 1:
The lens design uses a radially asymmetric rigidity distribution with a higher rigidity central optic portion and lower rigidity peripheral portion. This asymmetric structure creates a unique fit on the cornea that provides astigmatic correction without requiring cylindrical components or precise rotational orientation, simplifying the overall lens design and inventory requirements.
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 bimodulus design improves visual acuity by independently correcting astigmatic and presbyopic errors, reducing the need for precise lens alignment and inventory management, while enhancing comfort and oxygen permeability.
Implementation Method 1
engagement of the posterior surface against the eye deforms the posterior surface of the lens and so that the posterior surface has a shape diverging from the refractive shape of the cornea
Implementation Method 2
allowing for tear fluid to fill and maintain a radially symmetric spherical surface
Data Source
AI summary
Bimodulus multifocal ophthalmic lenses for correcting presbyopia include an inner optic portion characterized by a rigidity greater than a rigidity of an outer peripheral portion. When applied to an eye, the ophthalmic lenses are configured to provide one or more lenticular volumes between the posterior surface of the lens and the cornea. The ophthalmic lenses are further characterized by features on a surface of the lens for improving multifocal visual acuity. The disclosure further relates to methods of correcting presbyopia using the ophthalmic lenses.