Birefringent Intraocular Lens for Presbyopia Correction
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Solution Overview
Problem
Existing multifocal intraocular lenses (IOLs) for presbyopia suffer from significant pupil size dependence of visual acuity and light-scattering issues, such as ghosting and halos, which can lead to binocular inhibition and decreased vision quality.
Innovation Solution
A multifocal intraocular lens with a circularly birefringent material that refracts light differently based on polarization, providing an extended depth of focus through a unique optical power ratio, and using stimulus-orientable optically anisotropic constituents or self-assembling compounds to optimize focusing capabilities without diffractive patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multifocal IOL designs with spatially separate portions or diffractive structures are used, then multiple focal planes are achieved, but light-scattering issues such as ghosting and halos occur
Solution Approach 1:
The patent applies parameter changes by utilizing the birefringent property of the IOL material, which has different refractive indices for different polarization states of light. This creates different optical powers for different polarization components, achieving multiple focal planes through a fundamental optical parameter change rather than structural segmentation or diffractive patterns
Solution Approach 2:
The patent employs composite materials by using a birefringent material composition that combines multiple optical properties within a single homogeneous material structure. This composite material approach eliminates the need for separate optical zones or diffractive structures while achieving multifocality
2Adaptability or versatility
If multifocal IOL designs are used, then presbyopia is addressed, but significant pupil size dependence of visual acuity occurs
Solution Approach 1:
The birefringent material's optical power varies with the polarization state of light, creating a parameter-based multifocal mechanism that is independent of pupil size. This allows presbyopia correction to function effectively across different pupil conditions without the visual acuity dependence seen in conventional designs
3Adaptability or versatility
If conventional multifocal IOL designs are used, then focal separation is achieved, but binocular inhibition and decreased vision quality result
Solution Approach 1:
By using polarization state as the distinguishing parameter for different focal planes, the invention avoids the light-scattering and ghosting issues of conventional designs. This parameter-based approach maintains higher vision quality and reduces binocular inhibition while achieving effective focal separation
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 provides improved visual acuity with minimal pupil diameter dependence and eliminates light-scattering issues, offering a superior extended depth of focus without the drawbacks of existing IOL designs.
Implementation Method 1
a circularly birefringent material with a right-handed index of refraction nR for a light with a right-handed polarization, and a left-handed index of refraction nL for a light with a left-handed polarization
Implementation Method 2
stimulus-orientable optically anisotropic constituents, adapted to modify the multifocal intraocular lens to have an ordinary index of refraction no for a light with an ordinary polarization, and an extraordinary index of refraction ne for a light with an extraordinary polarization
Data Source
AI summary
A multifocal intraocular lens (MF-IOL) includes a circularly birefringent material with a right-handed index of refraction nR for a light with a right-handed polarization, and a left-handed index of refraction nL for a light with a left-handed polarization; and haptics, to position the multifocal intraocular lens inside a capsule of an eye; wherein the multifocal intraocular lens has a right-handed optical power DR for the light with the right-handed polarization, and a left-handed optical power DL for the light with the left-handed polarization, wherein DL/DR=(nL−1)/(nR−1). Some variations of the MF-IOL include stimulus-orientable optically anisotropic constituents. Some classes of the MF-IOL include a self-assembling optically anisotropic compound. A corresponding method of making a MF-IOL is comprising providing stimulus-orientable optically anisotropic constituents as part of an intraocular lens; orienting the optically anisotropic constituents by applying a non-stretching stimulus; and locking-in the oriented optically anisotropic constituents to form the multifocal intraocular lens.