High Refractive-Index Siloxy Polymers for Ophthalmic Devices
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Solution Overview
Problem
Current ophthalmic devices, such as intraocular lenses, face challenges with materials having low refractive indices, which require thicker optic portions and are prone to water absorption, leading to complications like light reflections and difficulty in achieving ideal folding and unfolding characteristics.
Innovation Solution
Development of siloxy-containing monomers, macromonomers, and polymers with high refractive indices, incorporating arylsiloxy-containing side groups that increase refractive index and are biocompatible, allowing for the creation of stable, flexible, and foldable ophthalmic devices with minimal incision requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If low water content hydrophobic acrylic materials are used to achieve high refractive index, then refractive index is improved, but water absorption occurs over time causing light reflections and glistenings
Solution Approach 1:
The patent uses composite materials by combining hydrophilic acrylic polymer chains with hydrophobic side groups (such as phenyl, naphthyl, or other aromatic groups) attached to the polymer backbone. This creates a material that has both hydrophilic characteristics (resisting water absorption) and hydrophobic characteristics (maintaining high refractive index), thereby resolving the contradiction between water stability and refractive index.
2Reliability
If high water content hydrophilic acrylic materials are used, then water stability is improved, but refractive index becomes low requiring thicker IOL optic portions
Solution Approach 1:
The patent applies local quality by creating a polymer structure where the main chain is hydrophilic (providing water stability) while specific side groups attached at local positions are hydrophobic aromatic groups (providing high refractive index). This localized differentiation of material properties allows the IOL to achieve both water stability and high refractive index simultaneously, avoiding the need for thicker optic portions.
3Ease of operation
If soft foldable materials are used to enable smaller incisions, then ease of operation is improved, but material stability and control over folding characteristics become difficult to achieve
Solution Approach 1:
The patent employs parameter changes by carefully adjusting the glass transition temperature (Tg) of the acrylic polymer through modification of the polymer structure and side group composition. By controlling Tg to be below body temperature but above room temperature, the material exhibits foldable characteristics at room temperature for surgical insertion, then stabilizes at physiological temperature in the eye, achieving both ease of operation and material stability.
Data Source
AI summary
Siloxy-containing monomers, macromonomers, or polymers have at least a siloxy-containing side group that comprises a refractive-index increasing substituent. Polymeric compositions comprising such siloxy-containing monomers, macromonomers, or polymers are advantageously used for making ophthalmic devices, such as intraocular lenses, contact lenses, corneal rings, corneal inlays, and keratoprostheses.