Zero-Step Diffractive Intraocular Lens for Presbyopia
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Solution Overview
Problem
Conventional multifocal ophthalmic lenses, including intraocular lenses (IOLs), often suffer from visual artifacts such as glare and halos due to the transitions between diffractive zones, particularly at intermediate distances, and fail to provide satisfactory visual performance in this range.
Innovation Solution
The design incorporates a diffractive profile with a repetitive pattern of echelettes, where at least one pair of adjacent echelettes is connected by a zero-step-height transition, reducing optical aberrations, and directs light in ascending proportions towards near, intermediate, and far focal lengths, with a significant portion directed towards far vision and a minimal portion towards near vision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional multifocal diffractive lenses use stepped transitions between echelettes to create multiple focal lengths, then the lens provides near and far vision correction, but visual artifacts such as glare and halos occur due to the abrupt transitions between diffractive zones
Solution Approach 1:
The patent changes the geometric parameter of the transition between echelettes from a stepped configuration to a continuous profile. The continuous diffractive profile eliminates abrupt height changes while maintaining the multifocal light distribution, thereby reducing visual artifacts like glare and halos that occur with conventional stepped transitions.
Solution Approach 2:
Instead of using the conventional approach of abrupt stepped transitions between diffractive zones, the patent inverts the transition approach by using continuous smooth profiles. This inversion of the transition method maintains the beneficial multifocal light separation while eliminating the harmful visual artifacts caused by abrupt boundaries.
2Reliability
If conventional multifocal lenses use multiple diffractive zones with non-zero step heights to direct light to different focal lengths, then the lens provides accommodation for near and far vision, but optical aberrations and straylight increase reducing visual performance
Solution Approach 1:
The patent modifies the step height parameter between adjacent echelettes from non-zero values to zero step height. This parameter change creates a continuous optical surface that reduces straylight and optical aberrations while maintaining the ability to direct light to multiple focal lengths, thereby improving overall visual performance and reliability.
3Adaptability or versatility
If diffractive lenses use traditional echelette geometry with non-zero step heights to achieve multifocality, then the lens can correct presbyopia, but the transitions between zones create dysphotopsia and reduce patient satisfaction
Solution Approach 1:
The patent changes the critical parameter of step height at echelette transitions from non-zero to zero, creating a continuous optical surface. This parameter modification maintains the presbyopia correction capability through multifocal light distribution while eliminating the dysphotopsia and patient discomfort caused by abrupt transitions in traditional designs.
Solution Approach 2:
The patent inverts the conventional transition approach between diffractive zones by using continuous profiles instead of stepped transitions. This inverted approach maintains the therapeutic effect of presbyopia correction while eliminating the harmful side effect of dysphotopsia, thereby improving patient satisfaction.
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
This configuration reduces straylight and other visual artifacts, enhancing visual performance across various distances, especially at intermediate ranges, by optimizing light distribution among focal lengths.
Implementation Method 1
Multifocal ophthalmic lenses (including contact lenses or the like) have also been proposed for treatment of presbyopia without removal of the natural crystalline lens. Diffractive optical surfaces, either monofocal or multifocal, may also be configured to provide reduced chromatic aberration.
Implementation Method 2
At least one of the at least two diffractive echelettes in the repetitive pattern is connected to an adjacent echelette by a step height of zero. The zero-step-height transition between at least one adjacent pair of diffractive echelettes is effective to reduce optical aberrations for a user, particularly straylight at the far vision.
Data Source
AI summary
Apparatuses, systems and methods for providing improved ophthalmic lenses, particularly intraocular lenses (IOLs), include features for reducing dysphotopsia effects, such as straylight, haloes and glare, in diffractive lenses. Exemplary ophthalmic lenses can include a diffractive profile that distributes light among a near focal length, a far focal length, and one or more intermediate focal length. The diffractive profile provides for minimized or zero step heights between one or more pairs of diffractive zones for reducing visual artifacts.