Contact Lens Thin Lower Area for Translation and Stabilization
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Solution Overview
Problem
Contact lenses with lower support structures can cause discomfort and reduced physiological tolerance due to their relative thickness, which affects the translation and stabilization mechanisms, particularly for lenses with multiple correction zones like those for presbyopia.
Innovation Solution
A contact lens design featuring a thin lower support area with a recess and internal clearance, allowing it to pass under the lower eyelid, similar in thickness to the upper edge, promoting mechanical and physiological compatibility, and incorporating a clearance on the internal face to enhance translation and stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the lower edge of the lens is made thick to provide lower support for abutment against the lower eyelid, then the lens stabilization and translation are improved, but the comfort and physiological tolerance are reduced
Solution Approach 1:
The lower edge of the lens is divided into two functional segments: a thick lower support portion (1.0-2.0mm) that provides abutment against the lower eyelid for stabilization, and a thin lower area portion (0.05-0.15mm) that reduces mechanical irritation. This segmentation allows each part to fulfill its specific function optimally without compromising the other.
Solution Approach 2:
Different thickness characteristics are assigned to different zones of the lower edge: the lower support zone has increased thickness for mechanical abutment function, while the lower area zone has reduced thickness for comfort. This local differentiation of properties resolves the contradiction between stabilization requirement and comfort requirement.
2Speed
If the lower edge is truncated to increase translation, then the lens translation capability is improved, but the rotation risk increases
Solution Approach 1:
The lower edge geometry is segmented into a truncated lower support portion that facilitates translation, and a curved lower area portion that matches the eyelid contour to prevent rotation. This segmentation allows the lens to translate smoothly while maintaining stable orientation.
Solution Approach 2:
The lower edge exhibits asymmetric geometry with different characteristics in different angular sectors: the lower support (200°-340°) has truncation for translation, while the lower area (340°-200°) has curvature for anti-rotation. This asymmetric design resolves the contradiction between translation and orientation stability.
3Device complexity
If a single lower support is used to simplify the lens structure, then the device complexity is reduced, but the lens centering capability is compromised
Solution Approach 1:
The lower area portion serves multiple functions simultaneously: it maintains lens orientation through eyelid interaction, contributes to translation facilitation, and provides additional stabilization. This multi-functionality compensates for having only a single lower support structure, resolving the contradiction between simplicity and centering capability.
Data Source
Figure 1~5
AI summary
The invention relates to a contact lens having at least two focal lengths, a single lower supporting element (1) enabling the lens to be moved in translation in relation to the eye and a region (9) in the lower part of the lens, which region (9) has an outer face connected to the rest of the outer face (E) of the lens by means of a recess and an inner face merging with the rest of the inner face (i) of the lens, said recess defining the lower supporting element (1). The lens is characterised in that the aforementioned region (9) is thin, having an average thickness (e4) of the same order of magnitude as the thickness (e1) of the upper edge (3) of the lens.