Rotationally Stabilized Contact Lens Design
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Solution Overview
Problem
Current contact lenses for astigmatic patients face a tradeoff between rotational stability and comfort, as designs that improve stability often increase thickness, leading to discomfort, and those that enhance comfort may compromise stability.
Innovation Solution
A contact lens design that optimizes non-circularity and thickness differential, using a matrixed set of peripheral geometries with noncircularity ranging from 95% to 60% and thickness differential from 0.1 mm to 0.4 mm, calculated to achieve optimal stabilization time and comfort, combining these factors to create a more effective and comfortable lens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If thickness differential is increased to improve rotational stability, then lens stability is improved, but lens thickness increases leading to reduced comfort
Solution Approach 1:
The patent applies asymmetry by designing a non-circular lens periphery with specific geometric parameters (e.g., horizontal diameter to vertical diameter ratio between 0.85:1 and 0.95:1). This asymmetric shape creates inherent rotational stability without relying solely on thickness differential, thereby improving stability while maintaining comfort by reducing the need for excessive thickness variations.
Solution Approach 2:
The patent optimizes specific geometric parameters of the lens periphery, including the horizontal diameter to vertical diameter ratio, arc lengths, and curvature radii. By carefully adjusting these parameters within specific ranges, the lens achieves rotational stability with minimized thickness differential, resolving the contradiction between stability and comfort.
2Stability of the object's composition
If non-circularity is increased to improve rotational stability, then lens stability is improved, but lens complexity and manufacturing difficulty increase
Solution Approach 1:
The patent introduces controlled asymmetry through a non-circular periphery defined by specific geometric relationships (e.g., horizontal diameter approximately 90-95% of vertical diameter). This level of asymmetry is sufficient to provide rotational stability while remaining manufacturable using conventional contact lens fabrication techniques, avoiding excessive complexity.
Solution Approach 2:
The patent specifies optimal ranges for geometric parameters (such as diameter ratios between 0.85:1 and 0.95:1, and arc length proportions) that balance rotational stability with manufacturability. These parameter optimizations ensure the lens can be produced using standard manufacturing processes without requiring complex tooling or techniques.
3Ease of operation
If thickness differential is reduced to improve comfort, then wearer comfort is improved, but rotational stability is compromised
Solution Approach 1:
The patent compensates for reduced thickness differential by implementing a non-circular periphery with specific geometric characteristics. The asymmetric shape (horizontal diameter 90-95% of vertical diameter) provides sufficient rotational stability even with minimal thickness variation, allowing comfort to be improved without sacrificing stability.
Solution Approach 2:
The patent combines two stabilization mechanisms: non-circular periphery geometry and thickness differential. By merging these approaches, the lens achieves rotational stability through the geometric asymmetry alone or in conjunction with minimal thickness variation, thereby improving comfort while maintaining stability.
4Stability of the object's composition
If non-circularity is optimized to improve rotational stability, then lens stability is improved, but lens design complexity increases
Solution Approach 1:
The patent implements a non-circular periphery with well-defined geometric parameters (horizontal diameter to vertical diameter ratio of 0.85:1 to 0.95:1). This systematic approach to asymmetry provides rotational stability while maintaining design simplicity through clear mathematical relationships, avoiding arbitrary complex shapes.
Solution Approach 2:
The patent optimizes specific geometric parameters within defined ranges (diameter ratios, arc lengths, curvature radii) to achieve rotational stability. By constraining parameters to specific ranges rather than allowing free variation, the design remains relatively simple while still providing effective stabilization.
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 2C~2D
AI summary
The invention provides an improved rotationally stabilized contact lens design and method of designing such a lens which minimizes stabilization time of the lens while maximizing the lens on-eye comfort. The lens and the method of designing the lens utilizes and combines non-circularity and thickness differential aspects resulting in equivalent or minimized stabilization time, ease of insertion and manufacturability as well as maximum comfort that is improved over that of what either aspect can achieve independently.