Layered Silicone Hydrogel Lenses for Persistent Surface Wettability

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Solution Overview

Problem

Silicone hydrogel contact lenses face challenges with maintaining hydrophilicity, wettability, and lubricity due to silicone migration and high water content leading to dehydration and discomfort, while requiring surface modifications that may not persist throughout the day.

Innovation Solution

A silicone hydrogel contact lens with a layered structural configuration featuring an inner silicone hydrogel layer surrounded by two outer hydrogel layers, each with higher water content and thickness, creating a water gradient and preventing silicone exposure, ensuring persistent hydrophilicity and lubricity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the water content of silicone hydrogel contact lens is increased to improve softness and comfort, then the lens becomes softer and more comfortable to wear, but the mechanical strength and rigidity of the lens deteriorate

Engineering Contradiction:

ImprovecomfortVSAvoidmechanical strength

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The patent applies local quality by creating a water content gradient within the lens structure, with higher water content (80-90%) at the surface layers for comfort and lower water content (40-60%) in the bulk material for mechanical strength. This spatial variation in water content allows different regions of the lens to have optimized properties for their specific functions.

Inventive Principle:

Principle #3Local quality

2Reliability

If the water content of silicone hydrogel contact lens is increased to improve biocompatibility, then the lens becomes more biocompatible, but the oxygen permeability of the lens deteriorates

Engineering Contradiction:

ImprovebiocompatibilityVSAvoidoxygen permeability

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses local quality by concentrating high water content (80-90%) in the surface layers that contact the eye for biocompatibility, while maintaining lower water content (40-60%) in the bulk material that contains the silicone oxygen transport channels. This allows the lens to be biocompatible at the interface with the eye while preserving oxygen permeability through the bulk material.

Inventive Principle:

Principle #3Local quality

3Ease of operation

If the water content of silicone hydrogel contact lens is increased to improve softness, then the lens becomes softer, but the lens becomes more susceptible to dehydration in the eye

Engineering Contradiction:

ImprovesoftnessVSAvoidwater loss

Core Design Contradiction:

Ease of operationVSLoss of substance

Solution Approach 1:

The patent applies local quality by placing high water content (80-90%) material at the surface layers for softness and comfort, while using lower water content (40-60%) bulk material that is less prone to dehydration. The gradient structure creates a water reservoir effect where the bulk material can supply water to the surface layers, reducing overall water loss.

Inventive Principle:

Principle #3Local quality

4Ease of operation

If surface modification is applied to silicone hydrogel contact lens to improve hydrophilicity, then the surface becomes more hydrophilic initially, but the hydrophilicity does not persist throughout the day

Engineering Contradiction:

ImprovehydrophilicityVSAvoidduration of hydrophilicity

Core Design Contradiction:

Ease of operationVSDuration of action of stationary object

Solution Approach 1:

The patent applies preliminary action by incorporating high water content (80-90%) hydrophilic polymer layers at the surface during lens fabrication, rather than applying surface modifications after lens production. This pre-built hydrophilic structure is inherently stable and does not require subsequent surface treatments that would degrade over time.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses composite materials by combining silicone hydrogel bulk material with hydrophilic polymer surface layers (such as polyacrylic acid, polyacrylamide, or polyethylene glycol). This composite structure integrates the oxygen permeability of silicone with the hydrophilicity of the polymer layers, creating a multi-functional material system.

Inventive Principle:

Principle #40Composite materials

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 lens maintains high oxygen permeability, reduces dehydration-induced discomfort, enhances biocompatibility, and provides long-lasting comfort by preventing silicone migration and promoting tear distribution.

Implementation Method 1

water diffusion through a lens from the posterior surface to the anterior surface

Methodology Applied

Scientific EffectWater diffusion: Diffusion

Implementation Method 2

a hydrated, crosslinked polymeric material that contains silicone and a certain amount of water within the lens polymer matrix at equilibrium

Methodology Applied

Scientific EffectHydrogel water retention: Hydrogel

Data Source

PatentUS20260042269A1Silicone hydrogel lenses with water-rich surfaces

Publication Date: 2026.02.12 ALCON INC

AI summary

The invention is related to a hydrated silicone hydrogel contact lens having a layered structural configuration: a lower water content silicone hydrogel core (or bulk material) completely covered with a layer of a higher water content hydrogel totally or substantially free of silicone. A hydrated silicone hydrogel contact lens of the invention possesses high oxygen permeability for maintaining the corneal health and a soft, water-rich, lubricious surface for wearing comfort.