Toric Contact Lens Aspherical Profile Spherical Aberration
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Solution Overview
Problem
Conventional toric contact lenses with uncontrolled optical power profiles fail to provide optimal vision correction, especially for patients with larger pupils or under low illumination, as they often accentuate inherent spherical aberration of the eye rather than compensating for it.
Innovation Solution
Designing a toric contact lens with a controlled optical power profile, featuring an optical axis with an anterior and posterior surface zone, where at least one zone is aspherical, combining to provide targeted cylindrical and spherical optical powers, and incorporating spherical aberration components described by Zernike terms to minimize power deviations and compensate for spherical aberration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional toric contact lens with uncontrolled optical power profile is used, then the lens can correct astigmatism with targeted cylindrical and spherical powers, but the lens accentuates inherent spherical aberration of the eye and fails to provide optimal vision correction
Solution Approach 1:
The patent applies local quality by creating non-uniform optical power distribution across the lens surface. The optical power varies as a function of radial distance from the optical axis, with different power zones designed to compensate for spherical aberration. This local variation in optical properties allows the lens to correct both astigmatism and spherical aberration simultaneously, improving vision quality without accentuating aberrations.
Solution Approach 2:
The patent changes the optical power parameter as a function of radial position. The optical power profile is designed to decrease or increase systematically with distance from the optical axis, creating a controlled power distribution that compensates for spherical aberration. This parameter change allows the lens to provide different optical corrections at different zones, resolving the contradiction between correcting astigmatism and avoiding spherical aberration.
2Stability of the object's composition
If a toric lens with purely positive power deviation is used, then the lens can provide consistent optical power across the lens, but the lens accentuates inherent spherical aberration especially for patients with larger pupils or under low illumination
Solution Approach 1:
The patent implements local quality by designing different optical power characteristics for different regions of the lens. The central zone and peripheral zone have different optical power profiles, allowing the lens to maintain stability in the center while compensating for spherical aberration in the periphery. This regional differentiation enables the lens to work effectively for patients with larger pupils without accentuating spherical aberration.
3Ease of manufacture
If a toric lens with uncontrolled optical power profile is used, then the lens can be manufactured with standard toroidal and spherical surfaces, but the lens may not provide optimal vision to patients, especially with larger pupils
Solution Approach 1:
The patent applies spheroidality by replacing the conventional spherical surface with an aspherical surface. The aspherical surface has a curvature that varies with radial distance from the optical axis, allowing control of the optical power profile. This curvature variation enables the lens to compensate for spherical aberration while maintaining manufacturability through established aspherical lens fabrication techniques.
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 controlled optical power profile ensures consistent optical performance across the lens, reducing spherical aberration and improving vision quality, particularly for patients with larger pupils or in low light conditions, by maintaining power deviations within specific diopter ranges and incorporating spherical aberration components.
Implementation Method 1
at least one of the first and second optical zone has an aspherical surface which is designed to provide, in combination with the surface of the other optical zone, a controlled optical power profile... incorporating spherical aberration components described by any one of fourth order, sixth order, eighth order Zernike spherical aberration-like terms
Data Source
AI summary
The present invention provides a toric contact lens having a controlled optical power profile. In addition, the invention provides a series of toric contact lenses, each having a series of different targeted cylindrical optical powers and a series of different targeted spherical optical powers, and each having a spherical aberration profile in which (1) the optical power deviations of the lens are substantially constant; (2) power deviation at a distance of 3 mm from the optical axis is from about −0.5 diopter to about −1.5 diopters; (3) power deviation at a distance of 3 mm from the optical axis is from about 0.2 diopter to about 1.0 diopter smaller than power deviations at a distance of 2 mm from the optical axis; or (4) there is a spherical aberration component described by any one of fourth order, sixth order, eighth order Zernike spherical aberration-like terms, or combination thereof, wherein the spherical aberration component has a value of −0.5 diopter to about −1.5 diopters at a distance of 3 mm from the optical axis.