Ultra-high Dk Contact Lens Material Synthesis

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Solution Overview

Problem

Rigid gas permeable contact lenses currently offer limited oxygen permeability, leading to eye fatigue and strain due to insufficient oxygen delivery to the cornea, with existing materials achieving Dk values of only up to 145, which is not sufficient for optimal corneal metabolism.

Innovation Solution

A method involving the reaction of fluoroalkyl methacrylate, alkyl glycol dimethacrylate, hydrophilic agents, and specific silane compounds under high pressure and inert atmospheres to produce ultra-high Dk materials with Dk values greater than 175, enhancing oxygen permeability and preventing microporous structure collapse.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional RGP contact lens materials are used, then lens rigidity is maintained, but oxygen permeability is insufficient (Dk values only up to 145)

Engineering Contradiction:
Improveoxygen permeabilityVSAvoidcorneal metabolic sufficiency
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters by incorporating fluorinated monomers (providing rigidity and hydrophobicity) combined with hydrophilic monomers and crosslinking agents. This parameter change enables the material to achieve ultra-high oxygen permeability (Dk>175) while maintaining the necessary mechanical properties for rigid contact lens functionality.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite polymer system combining multiple functional components: fluorinated monomers for structural integrity, hydrophilic monomers for oxygen transport, and crosslinking agents for network formation. This composite approach allows simultaneous optimization of oxygen permeability, lens rigidity, and corneal metabolic support.

Inventive Principle:
Principle #40Composite materials

2Quantity of substance

If oxygen permeability is increased to reduce eye fatigue, then corneal oxygen supply improves, but lens structural stability may be compromised

Engineering Contradiction:
Improveoxygen delivery to corneaVSAvoidlens structural stability
Core Design Contradiction:
Quantity of substanceVSStrength

Solution Approach 1:

The patent applies local quality by creating a crosslinked polymer network where specific regions have different functional properties. The crosslinked structure provides local structural stability while the hydrophilic channels within the network provide localized oxygen transport pathways, achieving both strength and high oxygen permeability simultaneously.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent utilizes a porous crosslinked polymer network structure that provides continuous channels for oxygen diffusion throughout the lens material. This porous structure enables ultra-high oxygen permeability (Dk>175) while the crosslinked framework maintains lens rigidity and structural integrity.

Inventive Principle:
Principle #31Porous materials

3Duration of action of moving object

If extended wear times are desired, then oxygen permeability must be increased, but conventional materials cause eye fatigue and strain

Engineering Contradiction:
Improvewear timeVSAvoideye fatigue and strain
Core Design Contradiction:
Duration of action of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent changes the oxygen permeability parameter to ultra-high levels (Dk>175) through specific monomer selection and crosslinking density optimization. This parameter change ensures sufficient oxygen delivery to the cornea during extended wear periods, preventing hypoxia-induced eye fatigue and strain while enabling longer comfortable wear times.

Inventive Principle:
Principle #35Parameter changes

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 resulting ultra-high Dk materials significantly increase oxygen delivery to the cornea, reducing eye fatigue and strain by achieving higher oxygen permeability, with the potential for extended wear times without compromising lens rigidity or requiring surface treatments.

Implementation Method 1

contacting and reacting: a fluoroalkyl methacrylate; an alkyl glycol dimethacrylate; a hydrophilic agent, such as methacrylic acid; a hydroxyalkyl tris(trimethylsiloxy)silane; a hydroxyalkyl terminated polydimethylsiloxane; and styrylethyltris(trimethylsiloxy)silane

Methodology Applied
Scientific EffectPolymerization: Photopolymerisation

Implementation Method 2

Oxygen for aerobic corneal metabolism is derived principally from the atmosphere. Therefore, the physiologic integrity of the cornea during wear of a gas-permeable soft or rigid contact lens is thought to be primarily dependent on the consumption of oxygen that passes through the lens

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP3814393B1Ultra-high dk material
Publication Date: 2022.11.02 ACUITY POLYMERS INC

AI summary

A method of producing an ultra-high Dk material includes contacting and reacting a fluoroalkyl methacrylate; an alkyl glycol dimethacrylate; a hydrophilic agent, such as methacrylic acid; a hydroxyalkyl tris(trimethylsiloxy)silane; a hydroxyalkyl terminated polydimethylsiloxane; and styrylethyltris(trimethylsiloxy)silane. The reaction is conducted within an inert atmosphere at a pressure of at least 25 pounds per square inch (PSI) and for a period of time and at a temperature sufficient to produce the ultra-high Dk material.