Surface-Modified Silicone Contact Lenses for Protein Deposition Control
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Solution Overview
Problem
Silicone ophthalmic devices, such as contact lenses, have hydrophobic, non-wettable surfaces that lead to issues with protein and lipid deposition, causing discomfort and inflammation, especially during extended wear, and existing surface modification methods using wetting agents or organic solvents are not environmentally friendly or durable.
Innovation Solution
A surface modified silicone ophthalmic device is created through a polymerization process using a monomeric mixture of hydrophilic monomers, monofunctional silicone monomers, anionic monomers, and crosslinking agents, followed by a cationic copolymer coating to enhance hydrophilicity and wettability, without the need for organic solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicone ophthalmic devices are made with standard hydrophobic surfaces, then manufacturing is simple and material properties are stable, but wettability is poor and protein/lipid deposition occurs causing discomfort and inflammation
Solution Approach 1:
The patent applies local quality by modifying only the surface layer of the silicone ophthalmic device while maintaining the bulk material properties. A hydrophilic coating layer is applied to the surface to improve wettability and reduce deposition, while the underlying silicone material retains its oxygen permeability and structural integrity. This resolves the contradiction by creating different properties at different locations of the same device.
Solution Approach 2:
The patent uses composite materials by combining hydrophobic silicone base material with a hydrophilic surface coating. This composite structure allows the device to simultaneously exhibit the oxygen permeability of silicone and the wettability of hydrophilic materials, thereby improving biocompatibility and reducing harmful deposits without compromising manufacturing simplicity.
2Reliability
If surface modification is applied to improve wettability, then comfort and biocompatibility improve, but existing methods use organic solvents that are environmentally harmful and coatings are not durable
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition and physical state of the coating process. Instead of using organic solvents, the invention employs aqueous-based solutions and controls parameters such as humidity, temperature, and coating thickness to achieve durable hydrophilic surfaces. This eliminates environmental harm while maintaining improved wettability and comfort.
Solution Approach 2:
The patent adopts a disposable approach by integrating the hydrophilic coating directly into the lens manufacturing process rather than applying it as a separate removable layer. This ensures the coating is durable for the lifespan of the lens while avoiding the need for environmentally harmful solvent-based applications and re-coating procedures.
3Duration of action of stationary object
If extended wear lenses are designed for high comfort standards, then surface hydrophilicity must be maximized, but hydrophobic silicone surfaces naturally repel water and accumulate deposits over time
Solution Approach 1:
The patent applies preliminary action by pre-modifying the surface of the silicone ophthalmic device with a hydrophilic coating during the manufacturing process. This preliminary surface treatment ensures that when the device is used for extended periods, the wettability is already optimized from the start, preventing deposit accumulation and maintaining comfort throughout the extended wear duration without requiring subsequent interventions.
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 results in a water-extracted, surface modified silicone hydrogel lens with high wettability and improved comfort, reducing protein and lipid deposition, suitable for extended wear without environmental harm.
Implementation Method 1
by increasing the hydrophilicity of a contact lens surface, the wettability of the contact lens can be improved
Implementation Method 2
the wettability of the contact lens can be improved
Implementation Method 3
the surface of the lens can affect the lens's susceptibility to deposition, particularly the deposition of proteins and lipids
Implementation Method 4
a silicone ophthalmic device which is a polymerization product of a silicone ophthalmic device-forming monomeric mixture
Implementation Method 5
one or more crosslinking agents
Implementation Method 6
The packaging solutions are sterilized and have an osmolality of at least about 150 mOsm/kg
Implementation Method 7
The packaging solutions are sterilized and have a pH of about 6 to about 9
Data Source
AI summary
A surface modified silicone ophthalmic device includes a silicone ophthalmic device which is a polymerization product of a silicone ophthalmic device-forming monomeric mixture containing (a) one or more hydrophilic monomers, (b) one or more monofunctional silicone monomers represented by a structure of Formula I:wherein R1, R2, R3, R4, R5, R6, R7, x and y are as defined herein, (c) one or more anionic ophthalmic device forming monomers, and (d) one or more crosslinking agents, and a surface coating on the silicone ophthalmic device, the surface coating including a cationic copolymer including (i) monomeric units derived from a cationic monomer having an ethylenically unsaturated reactive end group, and (ii) monomeric units derived from a hydrophilic monomer having an ethylenically unsaturated reactive group.