Multilayer Contact Lens Oxygen Delivery Design
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Solution Overview
Problem
Contact lenses with low or no gas permeability struggle to deliver sufficient oxygen to the cornea, leading to physiological and pathological ocular changes, as existing technologies fail to effectively modulate the thickness of polymer layers to achieve the required oxygen transmissibility for healthy corneal physiology.
Innovation Solution
A contact lens design featuring a layer with high oxygen permeability to compensate for low or non-gas permeable components, ensuring an adequate equivalent oxygen percentage is delivered to the cornea by optimizing the thickness of the polymer layer beneath these components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a contact lens component with low or no gas permeability is used, then the structural integrity and functional requirements of the lens are met, but the oxygen delivery to the cornea is insufficient
Solution Approach 1:
The contact lens is divided into multiple layers with distinct functions: a first layer containing the low gas permeability component for structural integrity, and a second layer with higher oxygen permeability specifically for oxygen delivery to the cornea. This segmentation allows each layer to optimize its specific function without compromising the other.
Solution Approach 2:
Different regions of the contact lens are assigned different oxygen permeability properties. The first layer has low gas permeability where structural support is needed, while the second layer has higher oxygen permeability where oxygen delivery is prioritized. This local differentiation resolves the contradiction between structural requirements and oxygen delivery.
2Object-affected harmful factors
If the thickness of the polymer layer is increased to deliver sufficient oxygen, then oxygen transmissibility improves, but the lens complexity and manufacturing difficulty increase
Solution Approach 1:
Rather than increasing the thickness of a single homogeneous layer, the lens is segmented into two distinct layers with different thicknesses and properties. The second layer is optimized for oxygen permeability and can be relatively thin, while the first layer provides structural support. This segmentation achieves sufficient oxygen transmissibility without excessive overall thickness or complexity.
Solution Approach 2:
The contact lens uses a composite structure combining two different polymer materials with complementary properties. The first polymer provides structural integrity with low gas permeability, while the second polymer provides high oxygen permeability. This composite approach achieves both structural and functional requirements without requiring excessive thickness.
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
This design effectively increases the equivalent oxygen percentage to the cornea, meeting the minimum oxygen delivery requirements for corneal health, even under conditions where the component has low or no oxygen permeability, thereby reducing the risk of corneal edema and improving user comfort.
Implementation Method 1
The coefficient Dk, where D being diffusivity (cm2/sec), a measure of how fast the oxygen moves through the material
Implementation Method 2
k being the solubility (ml O2/ml of material×mm Hg), a measure of how much oxygen is contained in the material
Data Source
AI summary
Contact lenses, methods and systems for accomplishing the requirement for biocompatibility of oxygen delivery to the eye, and the cornea in particular, when elements and components are used which reduce the transmissibility of oxygen and which require coverage of a significant area of the non-vascularized cornea. A contact lens assembly is provided, comprising: an anterior surface, a posterior surface and at least one element or component having a substantially low oxygen permeability disposed within the lens. The contact lens also includes a layer having an oxygen permeability greater than the aforementioned element or component. The thickness of this layer is such that the layer provides an equivalent oxygen percentage to the cornea beneath the aforementioned element or component.