Copolymerizable Azo Compounds for Ophthalmic Lens Materials
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Solution Overview
Problem
Current visible light absorbers for ophthalmic lenses may migrate, phase separate, or leach out, leading to toxicological issues and reduced light-blocking activity, and there is a need for compounds that are copolymerizable, inexpensive to synthesize, and efficient in absorbing light between 380 - 495 nm.
Innovation Solution
Development of novel azo compounds with reactive groups for covalent attachment to ophthalmic lens materials, specifically designed to absorb visible light in the 380 - 495 nm range, which can be synthesized in 3-4 steps from inexpensive starting materials without column chromatography, and are suitable for use in intraocular lenses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional visible light absorbers are physically entrapped in polymeric lens materials, then the lens material can block visible light, but the absorbers may migrate, phase separate, or leach out causing toxicological issues and loss of light-blocking activity
Solution Approach 1:
The patent combines the light-absorbing function with the polymeric lens material itself by incorporating visible light absorbers into the polymer network during polymerization. This merging ensures the absorbers become an integral part of the lens material, preventing migration, phase separation, and leaching while maintaining stable light-blocking activity throughout the lens lifecycle.
Solution Approach 2:
The patent applies preliminary action by covalently binding the visible light absorbers to the polymeric network during the polymerization process before the lens is implanted. This preliminary covalent attachment ensures long-term stability and prevents subsequent leaching or migration that would cause toxicological issues and loss of optical function.
2Reliability
If additional functional groups are added to absorbers to improve copolymerizability, then covalent attachment to lens material is achieved, but synthesis complexity and cost may increase
Solution Approach 1:
The patent employs parameter changes by modifying the chemical structure of visible light absorbers to include copolymerizable vinyl groups (acrylate or methacrylate functionalities). This structural parameter change enables direct copolymerization with lens materials using standard radical initiators, achieving covalent attachment without requiring complex multi-step synthesis or expensive column chromatography purification.
3Illumination intensity
If visible light absorbers are used to block light between 380-495 nm, then optical clarity in the blue spectrum is improved, but the absorbers must maintain sufficient solubility in lens material ingredients to prevent coalescence into light-interacting domains
Solution Approach 1:
The patent applies parameter changes by incorporating hydrophilic functional groups into the visible light absorber molecules to enhance their solubility in the hydrophilic environment of lens material ingredients. This parameter modification prevents phase separation and coalescence into light-scattering domains, ensuring homogeneous distribution and maintained optical clarity throughout the lens material.
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 azo compounds provide stable light absorption within the desired wavelength range, preventing migration and leaching, thus ensuring the optical clarity and safety of implantable ophthalmic lenses while being cost-effective to produce.
Implementation Method 1
These azo compounds are especially suitable for use as monomers that absorb a portion of visible light (approximately 380 - 495 nm)
Data Source
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AI summary
Azo compounds that block visible light are disclosed. These light absorbers are particularly suitable for use in intraocular lens materials.