Silicone Hydrogel Contact Lens Composition for Oxygen and Moisture

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Silicone hydrogel contact lenses face challenges in achieving high transparency, high oxygen permeability, and high moisturizing capability while maintaining manufacturing simplicity and reducing production costs, as well as issues with lipid absorption leading to blurred vision.

Innovation Solution

A silicone hydrogel composition comprising a silicone macromer, a hydroxy-functionalized silicone-containing monomer, and N-vinyl pyrrolidone, with specific molecular weight ranges and molar ratios, which enhances hydrophilicity and mutual solubility, resulting in lenses with improved moisture retention and transparency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If silicone monomer, macromer or prepolymer is used to make contact lenses, then oxygen permeability is improved, but wettability deteriorates due to hydrophobicity

Engineering Contradiction:

Improveoxygen permeabilityVSAvoidwettability

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent uses a composite material system combining silicone macromer with hydrophilic monomers (NVP, HEMA) and hydroxy-functionalized silicone monomer. This composite approach allows the lens to simultaneously achieve high oxygen permeability from the silicone component and good wettability from the hydrophilic components, resolving the contradiction between oxygen transmission and surface wetting properties.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the chemical parameters of the lens material by incorporating specific functional groups (amino groups from silicone macromer, hydroxyl groups from hydroxy-functionalized silicone monomer, and carbonyl groups from hydrophilic monomers). These parameter changes in molecular structure enable the material to possess both high oxygen permeability and improved wettability without requiring additional surface treatments.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If plasma process or hydrophilic polymers are added to improve wettability, then moisture retention is improved, but manufacturing complexity and production cost increase

Engineering Contradiction:

ImprovewettabilityVSAvoidmanufacturing process complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent merges the wettability improvement function into the base lens material itself by incorporating hydrophilic monomers and hydroxy-functionalized silicone monomer during polymerization. This eliminates the need for separate plasma treatment processes or additional hydrophilic polymer coatings, thereby simplifying the manufacturing process while maintaining good wettability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The lens material itself provides the wettability function through its inherent chemical composition. The hydrophilic groups within the polymer network enable the lens to self-moisten without requiring external treatments or additional functional layers, making the manufacturing process more straightforward and cost-effective.

Inventive Principle:

Principle #25Self-service

3Reliability

If silicone hydrogel is used to achieve high oxygen permeability, then oxygen transmission to cornea is improved, but lipid absorption increases causing blurred vision

Engineering Contradiction:

Improveoxygen transmissionVSAvoidlipid deposition

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the chemical parameters of the lens material by incorporating amino groups, hydroxyl groups, and carbonyl groups that create a hydrophilic surface environment. This parameter change in surface chemistry reduces the affinity for lipid deposits while maintaining the silicone backbone's high oxygen permeability, thereby resolving the contradiction between oxygen transmission and lipid resistance.

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 composition achieves high oxygen permeability, transparency, and moisturizing capability, reducing the likelihood of lens dryness and lipid deposition, thereby enhancing comfort and vision clarity.

Implementation Method 1

The silicone macromer, the hydroxy-functionalized silicone-containing monomer or a combination thereof is mutually soluble with N-vinylpyrrolidone

Methodology Applied

Scientific EffectMutual solubility: Solvation

Implementation Method 2

how to polymerize a lens forming composition containing a hydrophilic monomer and a silicone monomer, macromer or prepolymer

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentUS9046641B2Silicone hydrogel composition and silicone hydrogel contact lenses made from the composition

Publication Date: 2015.06.02 PEGAVISION CORP

AI summary

A silicone hydrogel composition is disclosed. The composition includes at least one silicone macromer, a hydroxy-functionalized silicone-containing monomer, a first hydrophibic monomer and at least one crosslinker, in which the first hydrophibic monomer is N-vinyl pyrrolidone. The silicone macromer and the hydroxy-functionalized silicone-containing monomer are mutually soluble with N-vinylpyrrolidone. Silicone hydrogel contact lenses prepared from the silicone hydrogel composition are also disclosed.