Stiff Optic Zone Soft Contact Lens for Astigmatism
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Solution Overview
Problem
Current toric contact lenses for astigmatism correction often require stabilization mechanisms to maintain orientation on the eye, which can be uncomfortable and less effective, especially for plus powered lenses, due to their reliance on eyelid interaction and thickness differentials.
Innovation Solution
The development of composite soft contact lenses with a central optic zone made from silicone hydrogels having a higher Young's modulus, allowing the lens to vault over the cornea without conforming to astigmatic geometry, creating a tear fluid lens that optically neutralizes corneal toricity, reducing the need for stabilization features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If toric contact lenses use stabilization mechanisms to maintain orientation on the eye, then lens orientation stability is improved, but comfort and effectiveness deteriorate due to reliance on eyelid interaction and thickness differentials
Solution Approach 1:
The patent removes stabilization mechanisms from the contact lens design entirely. By extracting the stabilization function, the lens eliminates the need for thickness differentials and eyelid interactions, thereby improving comfort and effectiveness while maintaining orientation stability through the tear fluid lens mechanism
Solution Approach 2:
The patent introduces a tear fluid lens as an intermediary between the contact lens and the cornea. This fluid lens acts as a mediator that optically neutralizes corneal toricity and maintains lens orientation without requiring mechanical stabilization features, thus resolving the contradiction between stability and comfort
2Ease of operation
If soft contact lenses wrap around the cornea, then comfort is improved, but optical correction capability deteriorates because a fluid lens is generally not found and tear fluid resembles a thin film
Solution Approach 1:
The patent applies local quality by creating a distinct tear fluid lens layer between the contact lens and cornea. This localized fluid layer provides the necessary optical correction for astigmatism while the rest of the soft contact lens maintains comfort by wrapping around the cornea, thus resolving the contradiction between comfort and optical correction capability
3Reliability
If rigid gas permeable contact lenses are used to correct astigmatism, then optical correction capability is improved, but comfort deteriorates
Solution Approach 1:
The patent employs composite materials by combining a soft contact lens material with a tear fluid lens layer. The soft lens provides comfort while the tear fluid lens provides astigmatism correction, effectively resolving the contradiction between comfort and optical correction capability that plagues rigid gas permeable lenses
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 design provides comfortable and effective correction of astigmatism and higher order aberrations by maintaining lens orientation without stabilization mechanisms, enhancing vision clarity and reducing discomfort.
Implementation Method 1
The development of composite soft contact lenses with a central optic zone made from silicone hydrogels having a higher Young's modulus, allowing the lens to vault over the cornea
Implementation Method 2
creating a tear fluid lens that optically neutralizes corneal toricity
Data Source
Figure 1a~1b
Figure 2
AI summary
A molded contact lens comprising a stiffer optic zone relative to the peripheral zone of the contact lens provides an optical element for correcting astigmatism without the need for or substantially minimizing the need for the correction of rotational misalignment. The higher elastic modulus optic zone vaults over the cornea thereby allowing a tear lens to form. The tear lens follows or assumes the shape of the back surface of the contact lens. The combination of the tear lens and the optical zone provide an optical element for correction of refractive error.