Wettable Hydrogel Contact Lens Surface Modification
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional hydrophilic contact lenses can cause wearer discomfort and eye irritation, leading to dry eye issues, and producing wettable silicone hydrogel contact lenses that balance oxygen permeability, cost, and processability remains a challenge.
Innovation Solution
The development of contact lenses with a surface comprising a reaction product of a polymerizable composition including a polyhydric alcohol and an ophthalmically acceptable acid, which maintains wettability and can be recharged, using a polymerizable composition comprising at least one hydrophilic monomer, a crosslinking agent, and an ophthalmically acceptable acid, ensuring the acid is immobilized and not extracted during manufacturing or wear, providing extended wettable surfaces without the need for organic solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hydrophilic contact lenses are used, then oxygen permeability is adequate, but wearer comfort deteriorates due to dry eye issues and eye irritation
Solution Approach 1:
The patent applies preliminary action by incorporating ophthalmically acceptable acids and polyhydric alcohols into the lens formulation before manufacturing. This pre-treatment ensures the lens surface is pre-conditioned with wetting agents that prevent dry eye issues during wear, eliminating the need for post-manufacturing coating steps.
Solution Approach 2:
The patent uses composite materials by combining silicone hydrogel base material with ophthalmically acceptable acids and polyhydric alcohols. This composite approach maintains the high oxygen permeability of silicone hydrogels while adding surface wetting properties through the acid-alcohol interaction, resolving the contradiction between oxygen transmission and wearer comfort.
2Reliability
If silicone hydrogel contact lenses are used to improve oxygen permeability, then oxygen transmission increases, but surface wettability deteriorates requiring additional processing steps
Solution Approach 1:
The patent merges multiple functions into a single integrated formulation: the silicone hydrogel provides oxygen permeability, the ophthalmically acceptable acid provides surface activation, and the polyhydric alcohol provides wettability. This combination eliminates the need for separate surface treatment steps, resolving the manufacturing complexity issue while maintaining high oxygen transmission.
Solution Approach 2:
The patent changes the chemical parameters of the lens surface by incorporating ophthalmically acceptable acids that react with polyhydric alcohols. This chemical modification alters the surface energy and wettability characteristics of the silicone hydrogel without changing its bulk oxygen permeability properties, allowing simultaneous optimization of both parameters.
3Ease of operation
If polyhydric alcohol is applied to lens surface to improve wettability, then surface wetting improves, but durability deteriorates due to extraction during manufacturing and wear
Solution Approach 1:
The patent introduces ophthalmically acceptable acids as intermediaries that chemically bind polyhydric alcohols to the lens matrix. The acid acts as a bridge between the hydrogel structure and the polyol, forming stable complexes that prevent polyol extraction during manufacturing and wear, thereby improving both application ease and composition stability.
Solution Approach 2:
The patent applies local quality by concentrating the acid-polyol interaction specifically at the lens surface region. The ophthalmically acceptable acid is incorporated in the lens formulation to create surface-localized binding sites that anchor polyhydric alcohols where they are most needed for wettability, while the bulk lens material maintains its original properties.
4Ease of manufacture
If conventional lens formulations are used, then manufacturing cost is low, but processability deteriorates due to additional wetting steps
Solution Approach 1:
The patent applies universality by designing a multi-functional lens formulation where the same components (ophthalmically acceptable acids and polyhydric alcohols) simultaneously provide surface activation, wettability enhancement, and polyol stabilization. This eliminates the need for separate manufacturing steps for each function, improving productivity without significantly increasing material costs.
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 contact lenses achieve high wettability and extended wear duration, maintaining surface wetting properties for up to 48 hours or more, with the ability to be recharged, thus addressing wearer comfort and manufacturing efficiency.
Implementation Method 1
A first polyhydric alcohol is present on at least the lens surface of the lens body... the acid interacts with the polyol with at least five hydroxyl groups to attach the polyol to at least the lens surface
Implementation Method 2
The ophthalmically acceptable acid is distributed in the reaction product within the lens body including some exposure at a lens surface thereof
Implementation Method 3
contact lenses comprising a lens body that comprises a reaction product of a polymerizable composition
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A contact lens is provided that has extended and rechargeable wettability. The contact lens includes a lens body that is a reaction product of a polymerizable composition. A first polyhydric alcohol having a 1, 2 diol or 1, 3 diol moiety is present on a lens surface of the lens body. A contact lens package including the contact lens, and methods of producing and using the contact lens, are also provided.