Embedded Diffractive Contact Lens with High RI Nanoparticles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current multifocal diffractive contact lenses are not commercially available for correcting presbyopia due to challenges in achieving a high enough refractive index difference between the lens material and the tear film, which requires a higher diffraction grating height, causing discomfort.
Innovation Solution
An embedded hydrogel contact lens with a diffractive insert made of a composite material comprising a hydrogel material and nanoparticles, such as titanium dioxide or zirconia dioxide nanocrystals, surface-functionalized with reactive or non-reactive functional groups, to achieve a higher refractive index and maintain optical transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard lens materials with refractive index of about 1.42 or less are used, then the contact lens maintains good wearing comfort and smooth surfaces, but the refractive index difference with tear film is only about 0.04, requiring higher diffraction grating height that causes discomfort
Solution Approach 1:
The patent applies composite materials by incorporating high refractive index nanoparticles (such as titanium dioxide, zirconia dioxide, or barium sulfate) into the hydrogel polymer matrix. This composite structure increases the overall refractive index of the contact lens material while maintaining the hydrogel's comfort properties, thereby achieving a greater refractive index difference with the tear film without compromising wearing comfort
Solution Approach 2:
The patent changes the refractive index parameter of the lens material by adding nanoparticles with high refractive indices (titanium dioxide: 2.6, zirconia dioxide: 2.1, barium sulfate: 2.3). This parameter modification allows the lens to achieve sufficient refractive index difference with tear film while maintaining smooth surfaces and comfortable wear
2Ease of manufacture
If high refractive index nanoparticles are incorporated into the hydrogel matrix, then the refractive index difference with tear film increases, but the optical transparency and light transmittance may be reduced
Solution Approach 1:
The patent applies local quality by carefully controlling the distribution, size (nanoscale), and concentration of high refractive index nanoparticles within the hydrogel matrix. The nanoparticles are dispersed at optimal concentrations and sizes to provide sufficient refractive index enhancement while maintaining optical transparency and light transmittance in the visible spectrum
Solution Approach 2:
The patent utilizes the porous hydrogel matrix structure to disperse and accommodate high refractive index nanoparticles. The hydrogel's three-dimensional network provides spaces for nanoparticle incorporation while maintaining optical clarity, allowing light to pass through without significant scattering or absorption
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 solution enables the creation of embedded diffractive multifocal hydrogel contact lenses with a higher oxygen transmissibility and improved comfort, while achieving the necessary refractive index difference for effective presbyopia correction.
Implementation Method 1
the insert in fully-hydrated state has a second refractive index that is at least 0.03 higher than the first refractive index
Implementation Method 2
multifocal diffractive contact lenses for correcting presbyopia
Data Source
AI summary
The invention provides a composite material suitable for making hydrogel contact lenses and especially diffractive inserts to be embedded in hydrogel contact lenses. A composite material of the invention has a relatively high refractive index (RI) and is composed of a hydrogel material and high RI nanoparticles which are distributed in the polymer matrix of the hydrogel material and present in an amount sufficient high to provide the composite material with a high RI but sufficient low to provide the composite material with a light transmissibility of 85% or greater in the range between 450 to 700 nm.