Multi-Ring Diffractive IOLs for Reduced Halos and EDOF Vision
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Solution Overview
Problem
Existing multifocal intraocular lenses (IOLs) suffer from visual symptoms such as dysphotopsia (glare and halos) and compromise intermediate vision, despite providing improved vision at near and far distances.
Innovation Solution
The design of a multifocal IOL with a diffractive profile featuring an interior echelette with a step height of no more than 0.2 wavelengths and an outer echelette with a step height of more than 0.2 wavelengths but less than two wavelengths, accompanied by a refractive zone, to enhance image quality across a wide range of foci without dysphotopsia.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multifocal IOLs use diffractive optical surfaces to direct light to multiple focal distances, then vision at near and far distances is improved, but visual symptoms such as dysphotopsia and halos occur
Solution Approach 1:
The diffractive profile is segmented into multiple echelettes with different step heights. The first echelette has a step height of 0.2-2.0 wavelengths while the second echelette has a step height of 0.05-0.2 wavelengths. This segmentation allows different portions of the light spectrum to be directed to appropriate focal points, reducing harmful visual symptoms while maintaining multifocal functionality.
Solution Approach 2:
Different regions of the lens are assigned different diffractive properties. The first echelette occupies a specific radial zone with one step height characteristic, while the second echelette occupies another radial zone with a different step height. This local differentiation optimizes light distribution for both near and far vision while minimizing dysphotopsia in specific pupil conditions.
2Power
If diffractive lenses use larger step heights to provide stronger diffractive power, then near vision is improved, but chromatic aberration and visual quality deteriorate
Solution Approach 1:
The invention changes the step height parameter across different echelettes. Instead of using a uniform large step height throughout, the first echelette uses a larger step height (0.2-2.0 wavelengths) for strong diffractive power, while the second echelette uses a smaller step height (0.05-0.2 wavelengths) to reduce chromatic aberration. This parameter variation optimizes both near vision power and overall image quality.
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 proposed design improves visual acuity and reduces halo intensity for all pupil sizes, particularly at smaller pupils, while maintaining good image quality across a range of distances.
Implementation Method 1
Multifocal IOLs may, for example, rely 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 providing improved extended depth of focus lenses. Exemplary ophthalmic lenses can include an optic including a diffractive profile including multiple rings, with the rings having step heights corresponding to a desired performance of the optic and configured to reduce adverse optical effects of the diffractive profile.