Toric Lens Phase Element Rotational Stability
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Solution Overview
Problem
Toric contact lenses and intraocular lenses face challenges with rotational instability and the need for a large inventory due to precise alignment requirements, leading to impaired vision and increased manufacturing costs, especially for correcting lower amounts of astigmatism.
Innovation Solution
Incorporating a phase-adjusting, non-diffractive optical element with a toric lens to extend the depth of focus, reducing sensitivity to rotational errors and allowing fewer lens units to cover a wider range of corrections, thereby mitigating astigmatism effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a toric lens with ballast is used to correct astigmatism, then rotational stability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts the ballast feature from the toric lens design, creating a spherical contact lens without ballast that corrects astigmatism through its spherical optical correction combined with the patient's existing spherical refractive error. This eliminates the complex ballast structures (prism ballasts, peri ballasts, thick/thin peripheral sections) while maintaining rotational stability.
Solution Approach 2:
The spherical contact lens performs multiple functions simultaneously: it provides spherical correction for the patient's baseline refractive error and corrects astigmatism through the interaction of this spherical correction with the eye's astigmatic components. This universal approach eliminates the need for specialized toric lens structures.
2Manufacturing precision
If a toric lens with precise axis offset is manufactured to correct astigmatism, then vision correction precision is improved, but manufacturing cost and inventory complexity increase
Solution Approach 1:
The patent eliminates the cylindrical correction component and associated axis offset specifications from the lens design. Instead of manufacturing toric lenses with precise cylindrical axes at various offsets (offered in 5-degree or 10-degree increments), the invention uses simple spherical lenses that require no axial alignment precision.
Solution Approach 2:
The patent changes the correction approach from cylindrical power with axial orientation parameters to spherical power parameters only. This parameter change eliminates the need for precise axis alignment and simplifies the prescription specifications from three parameters (spherical correction, cylindrical correction, and axis offset) to only spherical correction.
3Reliability
If a toric contact lens is fitted to correct astigmatism, then astigmatism correction effectiveness is improved, but rotational misalignment risk and fitting difficulty increase
Solution Approach 1:
The patent removes the toric optical zone and ballast features that cause fitting complexity. The spherical contact lens design eliminates rotational misalignment risks entirely, as spherical lenses have no axial orientation requirements. Fitting becomes as straightforward as spherical contact lens fitting, without needing to maintain specific cylindrical axis alignments.
4Adaptability or versatility
If a large inventory of toric lens units is maintained to cover various cylindrical corrections and axis offsets, then patient fitting options are improved, but manufacturing cost and inventory management complexity increase
Solution Approach 1:
The spherical contact lens serves as a universal design that can correct astigmatism across various prescription strengths without requiring different lens types. Instead of maintaining separate inventories for different cylindrical powers and axis offsets, practitioners need only spherical contact lens inventories, dramatically reducing the number of SKU variations while maintaining comprehensive prescription coverage.
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 solution provides increased certainty in astigmatism correction with reduced rotational misalignment risks, allowing for a more streamlined inventory and cost-effective production while maintaining effective vision correction across a broader diopter range.
Implementation Method 1
a phase-affecting, non-diffractive optical element operatively optically coupled to the toric lens and used to modify a phase of a wavefront passing through the toric lens
Data Source
Figure 1A
Figure 1B~1C
Figure 2~3
AI summary
An ophthalmic lens is presented. The lens includes a toric optical zone and a phase-affecting, non-diffractive optical element for extending depth of focus of imaging.