Copolymerizable Azo Compounds for Stable Ophthalmic Lens Light Absorption
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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, synthesized in 2-3 steps from inexpensive starting materials, which are suitable for use in intraocular lenses and other ophthalmic devices, allowing for stable light absorption within the desired spectrum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If visible light absorbers are physically entrapped in lens material, then ease of incorporation is improved, but stability and prevention of migration/leaching deteriorates
Solution Approach 1:
The patent combines the light-absorbing function with the polymer network structure by covalently bonding absorber molecules to polymeric chains. This merging of functions ensures the absorber becomes an integral part of the lens material, preventing migration and leaching while maintaining ease of incorporation through copolymerization processes.
Solution Approach 2:
The absorber molecules are covalently attached to polymeric chains before final lens assembly, ensuring stability is established in advance. This preliminary covalent bonding prevents subsequent migration or phase separation during lens fabrication and implantation procedures.
2Reliability
If absorbers are covalently bound to polymeric network, then stability and prevention of leaching is improved, but complexity of synthesis deteriorates
Solution Approach 1:
The patent employs universal reactive groups (acrylate, methacrylate, vinyl) that can participate in standard copolymerization reactions. These multi-functional groups allow the absorber to be incorporated into various polymeric networks using conventional radical polymerization techniques, reducing synthesis complexity while maintaining covalent bonding stability.
Solution Approach 2:
The patent modifies the molecular structure of absorbers by incorporating polymerizable functional groups with specific reactive parameters. These parameter changes enable the absorber to participate in free-radical copolymerization under standard conditions, simplifying the overall synthesis process while ensuring stable covalent attachment.
3Ease of operation
If absorber lacks sufficient solubility in lens material, then ease of handling is improved, but optical clarity deteriorates due to coalescence into domains
Solution Approach 1:
The patent introduces polar and nonpolar substituents at specific local positions on the absorber molecule to balance solubility characteristics. This local modification of molecular properties enables the absorber to dissolve uniformly in the hydrophobic polymeric lens material without coalescing into light-scattering domains, maintaining optical clarity while facilitating handling.
Solution Approach 2:
The patent designs absorber molecules with composite structural features combining hydrophobic aromatic cores and polar functional groups. This composite molecular architecture provides both compatibility with polymeric lens materials and sufficient solubility to prevent phase separation, ensuring optical clarity while maintaining ease of incorporation during fabrication.
4Ease of manufacture
If conventional olefinic polymerizable groups are used, then ease of copolymerization is improved, but absorption efficiency in 380-495 nm range deteriorates
Solution Approach 1:
The patent segments the absorber molecule into distinct functional regions: a light-absorbing chromophore segment (providing 380-495 nm absorption) and a polymerizable functional group segment (enabling copolymerization). This segmentation allows each segment to independently fulfill its function, maintaining both copolymerization ease and absorption efficiency.
Solution Approach 2:
The patent uses the polymerizable functional group as an intermediary that connects the light-absorbing chromophore to the polymeric network. This intermediary group facilitates copolymerization while the chromophore maintains its light-absorbing properties, achieving both ease of incorporation and absorption efficiency in the desired wavelength range.
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 and efficient visible light absorption between 380 - 495 nm, preventing migration and leaching, thus ensuring the optical clarity and safety of implantable ophthalmic lenses.
Implementation Method 1
visible light absorbers... efficient in absorbing light between 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.