Hydrogel Contact Lens Covalent Lubricious Coating
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Solution Overview
Problem
Conventional cast-molding techniques for producing non-silicone hydrogel contact lenses face issues such as the use of costly and environmentally unfriendly organic solvents, dimensional variations in plastic molds, and inadequate surface lubricity, leading to inconsistent lens quality and comfort.
Innovation Solution
A method involving a polyvinylalcohol-based hydrogel contact lens coated with a hydrophilic polymer using a water-based process to form stable 6-membered acetal rings, enhancing surface lubricity without compromising the lens's softness or optical quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional cast-molding technique with organic solvents is used, then contact lenses can be produced, but the process is costly and environmentally unfriendly
Solution Approach 1:
The patent changes the fundamental parameter of the manufacturing process by replacing organic solvents with water as the processing medium. This substitution transforms the chemical environment from harmful to environmentally friendly, while maintaining the ability to produce contact lenses through the hydrogel's water-based formulation and curing process
Solution Approach 2:
The patent converts the previously harmful organic solvent extraction step into a beneficial water-based process. By using water-soluble polyvinylalcohol prepolymers and water as the processing medium, the harmful organic solvent step is eliminated entirely, turning a harmful process into an environmentally benign one
2Productivity
If disposable plastic molds are used in conventional cast-molding, then contact lenses can be produced, but dimensional variations occur leading to low fidelity
Solution Approach 1:
The patent eliminates the need for expensive, complex disposable plastic molds by using simple glass or plastic dishes as molds. These simple molds can be reused and do not suffer from the dimensional instability issues of injection-molded plastic molds, thereby improving lens dimensional consistency while simplifying the manufacturing process
Solution Approach 2:
The patent uses simple dishes that can be precisely replicated and reused, ensuring consistent lens dimensions through the water-based hydrogel formulation that faithfully copies the mold geometry without the dimensional variations inherent in plastic injection molding
3Reliability
If DAILIES AquaComfort Plus lenses are used, then good optical quality and surface wettability are achieved, but surface lubricity is insufficient for superior wearing comfort
Solution Approach 1:
The patent creates a composite contact lens structure by combining the base polyvinylalcohol hydrogel material with surface-modifying components. The hydrogel matrix provides optical quality and wettability, while the crosslinked network and surface chemistry modifications enhance surface lubricity, achieving superior wearing comfort through material composition rather than simple coating
Solution Approach 2:
The patent applies different properties to different regions of the contact lens material. The bulk hydrogel provides optical clarity and wettability, while the crosslinked network structure and surface chemistry provide enhanced lubricity specifically at the lens surface, creating local quality differentiation that optimizes both optical performance and wearing comfort
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 method produces contact lenses with improved surface lubricity and consistency, maintaining the beneficial attributes of the preformed hydrogel lenses while enhancing wear comfort and reducing environmental impact.
Implementation Method 1
covalently attach a layer (or coating) of the hydrophilic polymer onto the preformed polyvinylalcohol-based hydrogel contact lens through 6-membered acetal rings
Data Source
AI summary
The invention is generally related to soft contact lenses which comprise a polyvinylalcohol-based hydrogel lens body and a durable lubricious coating thereon which are covalently attached to the polyvinylalcohol-based hydrogel lens body through 6-membered acetal rings and to a method for producing the same.