Superposed Diffractive Profiles Intraocular Lens
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Solution Overview
Problem
Current intraocular lenses, particularly refractive and refractive-diffractive lenses, face issues with adaptability for intermediate vision, light distribution dependency on pupil size, and significant light loss to higher refractive orders, leading to discomfort and reduced image quality.
Innovation Solution
An intraocular lens design featuring two superposed diffractive profiles on its anterior and posterior surfaces, creating distinct diffractive focal points of order +1 without pupil size dependency, along with a refractive focal point of order zero for far vision, allowing for focal points for near and intermediate vision, and utilizing higher order focal points to reinforce near vision, thereby optimizing light distribution and reducing losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a bi- or multi-focal refractive intraocular lens is used to provide multiple focal points for near and far vision, then the lens provides reduced contrast and may form halos in far vision with reduced luminosity, but it allows variable refractive power to address vision adaptation needs
Solution Approach 1:
The lens surface is segmented into multiple diffractive zones with different optical powers. Each zone directs light to a specific focal point (near, intermediate, or far vision), allowing the lens to provide multiple focal points while controlling light distribution to reduce halos and maintain contrast through precise zone design and apodization profiles
Solution Approach 2:
Different regions of the lens have locally optimized properties: central zones provide one set of focal points while peripheral zones provide another. The apodization profile varies locally across the lens surface to control light distribution, directing more light to certain focal points under specific pupil conditions, thereby reducing halos while maintaining adaptability
2Adaptability or versatility
If a refractive-diffractive intraocular lens is used to share light between far and near focal points, then the lens provides bifocal vision, but it creates discomfort in intermediate vision due to spacing between focal points
Solution Approach 1:
The diffractive profile is divided into multiple zones that create three distinct focal points: far vision (order 0), intermediate vision (order +1), and near vision (order +2). This segmentation ensures that intermediate vision has its own dedicated focal point rather than being a gap between far and near focal points, eliminating discomfort in intermediate distances
Solution Approach 2:
The lens uses apodization to dynamically change the distribution of light among the three focal points based on pupil size. Under different lighting conditions, the proportion of light directed to far, intermediate, and near focal points is adjusted, providing comfortable intermediate vision while maintaining bifocal functionality
3Adaptability or versatility
If diffractive profiles are used to create multiple focal points, then the lens provides multi-focal vision, but significant light is lost to higher refractive orders greater than 1
Solution Approach 1:
Instead of treating higher-order diffraction as waste, the lens design captures and redirects this light to useful focal points. The diffractive profile is engineered so that higher-order diffraction components are directed to the same or complementary focal points as the primary orders, converting what would be energy loss into additional light intensity at the desired focal points, thereby reducing overall light loss while maintaining multi-focal functionality
4Adaptability or versatility
If the diffractive profile is apodized with decreasing amplitude from the optical axis towards the outer edge, then the lens allows variation of light distribution between focal points according to pupil aperture, but it increases complexity of the lens design
Solution Approach 1:
The lens employs apodization, which continuously varies the amplitude parameter of the diffractive profile from the optical axis outward. This parameter change allows the lens to automatically adapt light distribution among focal points based on pupil size: under bright light (small pupil), more light goes to certain focal points, while in dim light (large pupil), distribution shifts. The complexity is managed through mathematical profiling that can be manufactured using standard lens fabrication techniques
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 lens provides improved adaptability and image quality by maintaining effective light distribution across focal points for far, intermediate, and near vision, minimizing light loss and pupil size dependency, and enhancing contrast and field depth.
Implementation Method 1
a diffractive lens creates a diffraction pattern forming one focal point on the optical axis per diffraction order
Implementation Method 2
A refractive lens converges light towards a focal point on the optical axis by refraction
Data Source
AI summary
An intraocular lens (1) including an anterior surface (4) and a posterior surface (5) and having a substantially antero-posterior optical axis (6). In this lens, one of these anterior and posterior surfaces includes a first diffractive profile (9) forming at least one first diffractive focal point (11) of order +1 on said optical axis, and a second diffractive profile (10) forming a second diffractive focal point (12) of order +1 on said optical axis which is distinct from the first diffractive focal point of order +1. At least one portion of said second diffractive profile is superposed to at least one portion of the first diffractive profile.