Toric Continuous Focus Intraocular Lens with Zonal Aberration Balancing
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Solution Overview
Problem
Existing multifocal intraocular lenses suffer from visual confusion and inefficient light energy use due to multiple peaks in the Modulation Transfer Function (MTF) curves and sensitivity to corneal aberrations, compromising optical performance across varying pupil sizes and corneal profiles.
Innovation Solution
Design of a monofocal intraocular lens with toric surfaces featuring zones with alternating signs for wavefront aberration components, optimized using annular terms to maintain MTF values and reduce sensitivity to corneal aberrations, ensuring a single peak in the MTF curve and continuous energy distribution across focal distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multifocal lenses are used to provide multiple focal planes, then vision range is improved, but visual confusion and inefficient light energy use occur due to multiple peaks in MTF curves
Solution Approach 1:
The patent changes the optical parameters by introducing toric surfaces with specific zone configurations that create a continuous focus effect. The lens zones are designed with specific powers and positions to eliminate discrete focal peaks while maintaining continuous vision across a range of distances, transforming the MTF curve from multiple peaks to a single continuous peak.
Solution Approach 2:
The patent employs composite optical design combining toric surfaces with specific zone configurations. The lens integrates multiple functional zones (central zone, intermediate zone, peripheral zone) with different optical powers and aberration characteristics to achieve both extended depth of focus and reduced sensitivity to corneal aberrations simultaneously.
2Adaptability or versatility
If conventional refractive or diffractive multifocal designs are used, then multiple focal planes are achieved, but sensitivity to corneal aberrations increases compromising optical performance
Solution Approach 1:
The patent applies local quality optimization by designing different zones with specific optical characteristics tailored to their functions. The central zone provides distance vision with specific aberration compensation, the intermediate zone handles mid-range vision, and the peripheral zone manages near vision. Each zone is optimized for its specific focal range while collectively reducing overall sensitivity to corneal aberrations.
Solution Approach 2:
The patent converts the harmful effect of corneal aberrations into a beneficial outcome by designing the lens zones to compensate for these aberrations. The toric surface zones are specifically configured to counteract common corneal aberrations, transforming what would normally be a performance-degrading factor into an opportunity to enhance optical quality across different focal distances.
3Adaptability or versatility
If diffractive lenses with low-power add profile are used, then multifocality is provided, but light energy is lost due to symmetrical light division resulting in multiple peaks in MTF
Solution Approach 1:
The patent introduces asymmetry in the lens zone configuration, particularly in the peripheral zone design. Instead of symmetrical light division that creates multiple peaks, the asymmetric toric surface zones are configured to create a continuous, skewed focus distribution. This asymmetric design concentrates light energy more effectively across the focal range, eliminating the energy loss associated with symmetrical diffractive designs.
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 provides sharp optical images over a wide range of corneal aberrations and pupil sizes, maintaining high MTF values across spatial frequencies, reducing photic phenomena, and improving vision clarity across multiple focal planes.
Implementation Method 1
an optic with an anterior surface and a posterior surface disposed about an optical axis. At least one of the anterior surface and the posterior surface has a toric shape and at least one of the anterior surface and the posterior surface includes a combination of zones in the surface with results having alternating signs for a wavefront aberration component defined using annular terms for balancing focus and maintaining MTF at different spatial frequencies
Data Source
AI summary
An intraocular lens including an optic having an anterior surface and a posterior surface disposed about an optical axis is provided. At least one of the anterior surface and the posterior surface has a toric shape and at least one of the anterior surface and the posterior surface including a combination of zones in its surface with alternating signs for a wavefront aberration component defined using annular terms for balancing focus to maintain modulation transfer function (MTF) values at different spatial frequencies. The intraocular lens may be monofocal or may be multifocal, depending on the specific implementation.