Soft Contact Lens Thickness Zoning for Corneal Reshaping
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Solution Overview
Problem
Existing rigid contact lenses are effective for non-surgical corneal reshaping but lack comfort due to high stiffness, while soft contact lenses are ineffective for intentional corneal reshaping, and there is a need for a soft contact lens that can deliver the performance of rigid lenses for temporary refractive error reduction.
Innovation Solution
The development of a soft contact lens with strain energy zones and variable thickness to create central and peripheral compression forces, enhancing corneal reshaping by altering the cornea's curvature, and incorporating regions with controlled water vapor transmissibility for comfort and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rigid contact lenses are used for corneal reshaping, then refractive error reduction is achieved, but lens comfort deteriorates due to high stiffness
Solution Approach 1:
The patent changes the material parameter from rigid to soft by using hydrogel or silicone hydrogel materials with low modulus of elasticity (0.25-2.0 MPa), while maintaining corneal reshaping effectiveness through strategic thickness variations and strain energy incorporation rather than relying on material stiffness
Solution Approach 2:
The lens combines soft hydrogel or silicone hydrogel base material with incorporated strain energy elements, creating a composite structure that provides both comfort from the soft material and reshaping force from the strain energy zones
2Ease of operation
If soft contact lenses are used for comfort, then lens comfort is improved, but corneal reshaping effectiveness deteriorates
Solution Approach 1:
The lens is segmented into multiple functional zones with different thicknesses: central zone, intermediate zone, and peripheral zone, each contributing differently to corneal interaction. The strain energy is also segmented into specific regions (central, mid-peripheral, peripheral) that independently contribute to the overall reshaping mechanism
Solution Approach 2:
The patent adds the dimension of thickness variation to the traditionally uniform soft lens design. By creating a three-dimensional thickness profile with multiple zones of varying thickness, the lens gains corneal reshaping capability while maintaining the comfort benefits of soft material
3Ease of manufacture
If uniform thickness is used in soft contact lenses, then manufacturing is simplified, but corneal reshaping effectiveness deteriorates
Solution Approach 1:
The lens thickness is segmented into multiple discrete zones (central, intermediate, peripheral) with specific thickness ranges, creating a stepped profile that can be manufactured using conventional techniques while achieving the desired corneal interaction pattern
Solution Approach 2:
Different regions of the lens are given different thickness qualities to perform specific functions: the central zone (0.03-0.15mm) for primary reshaping, intermediate zone (0.15-0.30mm) for transition, and peripheral zone (0.30-0.50mm) for stability and comfort, with each zone optimized for its local function
4Ease of operation
If high water vapor transmissibility is used in contact lenses, then corneal comfort is improved, but lens stability deteriorates due to reduced adherence
Solution Approach 1:
The lens applies local quality by creating specific zones with different water vapor transmissibility characteristics: high WVT zones (thin regions) for comfort and low WVT zones (thick regions) for stability and adherence, allowing both requirements to be satisfied in different locations
Solution Approach 2:
The patent uses thickness as an additional dimension to control water vapor transmissibility, creating a three-dimensional transmissibility profile that varies across the lens surface, with thin central zones for comfort and thick peripheral zones for stability
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 soft contact lens effectively reshapes the cornea to reduce refractive errors, provides comfort comparable to soft lenses, and maintains stability through controlled water vapor transmissibility and adherence forces.
Implementation Method 1
a medium residing between the anterior surface and the posterior surface, wherein the medium has an oxygen permeability and a water vapor permeability
Implementation Method 2
The modulus of elasticity of rigid gas permeable materials is inversely correlated with their oxygen permeability (Dk)
Data Source
AI summary
Ophthalmic devices and related methods are provided for management of water vapor transmissibility, delivery of pharmaceutical agents, and non-surgical corneal reshaping. In some embodiments, an ophthalmic device comprises an anterior surface facing away from an eye, a posterior surface facing toward the eye, a medium residing between the anterior surface and the posterior surface, wherein the medium has an oxygen permeability and a water vapor permeability, a first region having a first thickness of the medium, the first region having a water vapor transmissibility above a first minimum value and an oxygen transmissibility above a second minimum value, and a second region having a second thickness of the medium, the second region having a water vapor transmissibility below a third minimum value and an oxygen transmissibility above a fourth minimum value, wherein the second thickness is greater than the first thickness.