Aspheric Toric Intraocular Lens Aberration Correction
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Solution Overview
Problem
Traditional intraocular lenses (IOLs) are limited in their ability to correct vision across a range of object distances and do not effectively mitigate both corneal astigmatism and spherical aberrations simultaneously without compromising lens quality and resolution.
Innovation Solution
The development of intraocular lenses that incorporate both toricity and asphericity on separate or combined surfaces, allowing for variable asphericity across different meridians to correct a range of aberrations, including astigmatism and spherical aberrations, while maintaining high lens quality and resolution efficiency exceeding 4/6.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional spherical IOLs are used, then the lens structure is simple and easy to manufacture, but the ability to correct vision across a range of object distances is limited and cannot effectively mitigate corneal astigmatism and spherical aberrations
Solution Approach 1:
The lens surface is segmented into multiple functional zones with different asphericity values. The first aspheric surface has a first asphericity value while the second aspheric surface has a second asphericity value, allowing each zone to correct specific aberrations. This segmentation enables simultaneous correction of corneal astigmatism and spherical aberrations without creating a completely complex lens design.
Solution Approach 2:
Different regions of the lens are given different asphericity characteristics. The patent applies variable asphericity where the first aspheric surface and second aspheric surface have different asphericity values, allowing local optimization for correcting specific aberrations in different zones of the lens while maintaining overall simplicity.
2Reliability
If toric and aspheric surfaces are combined on a single lens, then multiple aberrations can be corrected simultaneously, but the manufacturing process becomes more complex
Solution Approach 1:
The manufacturing process is segmented into separate steps for creating the toric and aspheric surfaces. The lens is first formed with a toric surface to correct astigmatism, then an aspheric surface is added to correct spherical aberrations. This segmentation allows each surface to be optimized and manufactured using established processes while achieving combined aberration correction.
Solution Approach 2:
The patent merges toric and aspheric surface designs into a single lens structure where both surface types are integrated. By combining these surfaces, the lens can correct multiple aberrations simultaneously, and the merging is achieved through coordinated design of the first and second aspheric surfaces with different asphericity values.
3Reliability
If variable asphericity is applied across different meridians, then correction of higher order aberrations is improved, but the lens design complexity increases
Solution Approach 1:
Variable asphericity is applied locally across different meridians of the lens. The first aspheric surface and second aspheric surface have different asphericity values that are optimized for specific meridianal requirements. This local variation enables correction of higher order aberrations like coma and trefoil while maintaining a manageable design complexity through systematic application of asphericity.
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
These lenses provide excellent vision across various object distances, effectively reducing or eliminating the shortcomings of prior art methods by enhancing image contrast and depth of field, with the ability to correct multiple aberrations such as coma, trefoil, and higher-order aberrations, and can be manufactured using existing processes.
Implementation Method 1
Intraocular lenses (IOLs) are routinely implanted in patients' eyes during cataract surgery to replace the natural crystalline lens or to compensate for the lost optical power
Data Source
AI summary
An aspheric toric intraocular lens (IOL) having toricity and asphericity in a single lens. The toricity and asphericity may be provided on separate surfaces, such as an anterior surface and a posterior surface, or the toricity and asphericity may be combined onto a single surface. The edge thickness may be varied sinusoidal to maintain equal edge thickness at 45 degree meridian.