Contact Lens Stabilization Zones for Astigmatism Correction
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Solution Overview
Problem
Contact lenses for astigmatism correction often rotate and deviate during wear, leading to poor correction performance due to instability, which existing stable structures fail to adequately address.
Innovation Solution
A contact lens design featuring an optical zone surrounded by a peripheral zone with symmetrically arranged stabilization zones that gradually thicken, including specific elevation boundaries and slopes, to maintain the lens in a fixed position by utilizing the eyelids' pressure during blinking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing stable structures are used for contact lens, then the lens can maintain position for a long time, but the lens still rotates and deviates during wear causing poor correction performance
Solution Approach 1:
The contact lens incorporates stabilization zones with specific thickness variations (0.15-0.35mm height difference from base curved surface) located at precise radial distances (5.5-6.25mm from geometric center) to create localized stable regions. These zones have controlled slopes (first slope <0.2, second slope >0.6) that provide differential friction against the eyelid, ensuring the lens maintains proper orientation without rotating during wear.
Solution Approach 2:
The stabilization zones are pre-formed on the contact lens surface with specific geometric characteristics before佩戴. The zones include elevation starting boundaries at defined angles (+55° to +75° and −55° to −75° from horizontal axis) that anticipate and prevent rotation by creating predetermined stable contact points with the eyelid during blinking.
2Stability of the object's composition
If stabilization zones with specific thickness are added to the contact lens, then the lens positioning stability is improved, but the device complexity increases
Solution Approach 1:
The peripheral zone of the contact lens is segmented into two distinct regions: a base curved surface and stabilization zones with varying thickness. The stabilization zones are further divided into upper and lower portions with specific elevation boundaries, creating a multi-segmented structure that provides stable positioning through controlled interaction with the eyelid at different locations.
Solution Approach 2:
The stabilization zones introduce thickness variation (0.15-0.35mm height difference) as an additional dimensional feature to the otherwise two-dimensional contact lens surface. This third dimension (z-height) creates stable contact points with the eyelid without adding lateral complexity to the lens design.
Data Source
AI summary
A contact lens comprises an optical zone and a peripheral zone. The optical zone is used for vision correction. The peripheral zone surrounds the optical zone. The optical zone and the peripheral zone jointly define a geometric center and a horizontal axis passing through the geometric center. Two stabilization zones symmetrically arranged relative to the geometric center are formed in the peripheral zone. These stabilization zones gradually thicken relative to a base curved surface of the peripheral zone.