Diffractive IOL Echelettes for Dysphotopsia Reduction
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Solution Overview
Problem
Current multifocal intraocular lenses (IOLs) often result in undesirable visual effects such as dysphotopsia (glare or halos) and compromised intermediate vision, limiting their ability to provide clear vision across a wide range of distances without these issues.
Innovation Solution
The development of ophthalmic lenses with a unique diffractive profile featuring a plurality of echelettes, where each echelette has a distinct profile in r-squared space and is connected to adjacent echelettes by varying step heights, including some with zero step height, to enhance light distribution and reduce visual artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multifocal IOLs are used to provide vision at multiple distances, then near and far vision are improved, but intermediate vision is compromised and dysphotopsia occurs
Solution Approach 1:
The lens is divided into multiple discrete diffractive zones (echelettes) with different optical powers, where each zone directs light to a specific focal distance. This segmentation allows independent optimization of each zone's contribution to reduce dysphotopsia while maintaining multi-distance vision capability
Solution Approach 2:
Each diffractive zone is assigned a specific optical power and light distribution characteristic tailored to its radial position. The step heights between zones are varied locally to control light transfer and minimize halos, with inner zones having different properties than outer zones
2Ease of manufacture
If conventional diffractive profiles are used, then manufacturing is simplified, but visual performance and depth of focus are limited
Solution Approach 1:
The diffractive profile employs asymmetric step heights between adjacent zones rather than uniform steps. This asymmetry optimizes light distribution across different focal distances and reduces visual artifacts, achieving superior visual performance while remaining manufacturable through standard techniques
3Manufacturing precision
If monofocal IOLs are used, then visual quality at one distance is excellent, but vision at other distances requires spectacles
Solution Approach 1:
The IOL is designed to perform multiple functions simultaneously by incorporating diffractive zones with different optical powers in a single lens. This allows the lens to provide focused vision at near, intermediate, and far distances without requiring multiple separate lenses or spectacles
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 solution effectively reduces dysphotopsia and improves visual performance across a wide range of distances, including intermediate vision, by optimizing the diffractive profile of the lenses, thereby enhancing the depth of focus and image quality.
Implementation Method 1
Multifocal IOLs have relied on a diffractive optical surface to direct portions of the light energy toward differing focal distances
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
AI summary
Apparatuses, systems and methods for providing improved ophthalmic lenses, particularly intraocular lenses (IOLs), include features for reducing dysphotopsia effects, such as haloes and glare, in extended range of vision lenses. Exemplary ophthalmic lenses can include an optic including a first surface and a second surface each disposed about an optical axis and extending radially outward from the optical axis to an outer periphery of the optic. A diffractive profile including a plurality of echelettes is disposed on the first surface such that no echelette on the first surface repeats between the optical axis and the outer periphery of the optic.