Diffractive IOL Echelette Profiles for Extended Depth of Focus
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Solution Overview
Problem
Existing multifocal intraocular lenses (IOLs) often cause dysphotopsia and compromise intermediate vision, while conventional diffractive profiles with uniform echelette widths fail to provide a smooth, extended range of vision.
Innovation Solution
Incorporating a diffractive profile with echelettes of varying widths in r-squared space to distribute light to multiple focal distances, reducing symmetry in transition zones and minimizing visual symptoms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional diffractive profiles with uniform echelette widths are used, then the lens structure is simple and easy to manufacture, but the depth of focus is limited and intermediate vision is compromised
Solution Approach 1:
The patent applies asymmetry by varying the widths of echelettes in the diffractive profile. Instead of uniform widths, the echelettes have different widths in r-squared space, creating an asymmetric pattern that extends the depth of focus and improves intermediate vision while maintaining manufacturability
Solution Approach 2:
The patent implements local quality by making each echelette have a specific width tailored to its position in the diffractive profile. This local variation in echelette widths allows different regions of the lens to contribute differently to light distribution, achieving extended depth of focus across multiple focal distances
2Adaptability or versatility
If multifocal IOLs are used to provide vision at multiple distances, then the range of vision is extended, but dysphotopsia symptoms such as glare and halos increase
Solution Approach 1:
The patent changes the parameters of the diffractive profile by varying echelette widths in r-squared space. This parameter variation creates a more natural distribution of light energy across focal distances, reducing the intensity of stray light that causes dysphotopsia while maintaining extended range of vision
Solution Approach 2:
The patent converts the potential harm of light scattering (which causes dysphotopsia) into a benefit by using varied echelette widths to distribute light more evenly across focal distances. The irregular pattern reduces concentrated stray light while maintaining useful light distribution for extended depth of focus
3Device complexity
If diffractive profiles with regular echelette patterns are used, then the lens design is symmetric and simple, but the transition zones create visual symptoms and disrupt smooth focus
Solution Approach 1:
The patent deliberately introduces asymmetry in the echelette widths to break the regular pattern that causes visual symptoms. The varied widths in r-squared space create irregular transition zones that reduce the formation of halos and other dysphotopsia while maintaining design simplicity
Solution Approach 2:
The patent inverts the conventional approach by using irregular echelette widths instead of regular patterns. This inversion of the standard symmetric design eliminates the visual symptoms caused by regular transition zones while achieving smooth focus transitions across the diffractive profile
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 a smooth, extended depth of focus and improved visual performance across a range of distances, reducing glare and halos, and enhancing intermediate vision.
Implementation Method 1
Diffractive lenses have a diffractive profile which confers the lens with a diffractive power that contributes to the overall optical power of the lens
Implementation Method 2
Diffractive monofocal and multifocal lenses can make use of a material having a given refractive index and a surface curvature which provide a refractive power
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
Apparatuses, systems and methods for providing improved ophthalmic lenses, particularly intraocular lenses (IOLs), include features for providing improved extended depth of focus lenses. Exemplary ophthalmic lenses can include an optic including a diffractive profile including at least one set of echelettes, each echelette of the set having a different width in r-squared space than any other echelette of the set and the at least one set of echelettes repeating at least once upon the optic.