Ophthalmic Lens With Phase-Shift Structure for Extended Intermediate Vision
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Solution Overview
Problem
Conventional intraocular lenses (IOLs) lack an extended depth of focus, particularly for intermediate vision, necessitating additional eyewear for near and intermediate vision correction, and depth of focus diminishes with age.
Innovation Solution
An ophthalmic lens with a multi-layered surface profile comprising a phase shift structure, zonal structure, and base structure, featuring a trapezoid phase shift and inner power zone to enhance depth of focus and improve intermediate vision, while maintaining distance vision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional intraocular lenses are used to provide improved distance performance, then distance vision is improved, but intermediate vision depth of focus is insufficient
Solution Approach 1:
The lens surface is divided into multiple functional zones: a central optical zone with a phase shift structure for extending depth of focus, and a peripheral zone with base curvature for distance vision. This segmentation allows different regions to serve different visual functions simultaneously, resolving the contradiction between distance vision performance and intermediate vision depth of focus
Solution Approach 2:
The phase shift structure is applied locally to the central portion of the lens surface, creating a trapezoidal profile that selectively modifies light paths for intermediate and near vision while leaving the peripheral regions unchanged for distance vision. This local modification enables the lens to provide extended depth of focus without compromising distance vision performance
2Adaptability or versatility
If the lens surface is modified to extend depth of focus, then intermediate vision is improved, but visual disturbances may increase
Solution Approach 1:
The phase shift structure creates dynamic light path modulation where light waves are progressively delayed across the transition region, enabling continuous focus adjustment rather than discrete focal points. This dynamic approach reduces visual disturbances by creating a smoother focus transition compared to traditional multifocal designs
Solution Approach 2:
The transition region with linearly varying phase acts as an intermediary between the central optical zone and peripheral zone, smoothly bridging the different optical functions and reducing abrupt transitions that cause visual disturbances such as halos and glare
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 extends depth of focus up to 2.38 D, improving visual acuity by 0.2 for pupil diameters of 2 mm to 6 mm, and maintains clear distance vision without additional visual disturbances.
Implementation Method 1
the transition region is adapted such that a phase of radiation incident thereon varies linearly over at least a portion of the radial extent between the first boundary and the second boundary so as to generate a phase shift between the first and second boundaries
Data Source
AI summary
The present disclosure provides an ophthalmic lens (such as an IOL) that is designed to enhance depth of focus for intermediate vision performance, while maintaining distance vision. The lens may include an optic having an anterior surface and a posterior surface disposed about an optical axis. One of the surfaces (e.g., the anterior surface) may have a surface profile involving a superposition of at least three structures or profiles, including a base structure, a phase shift structure having an inner region, an outer region and a transition region, and a zonal structure having an inner power zone and an outer transition zone.