Contact Lens Surface Modulus Variation for Wearing Comfort
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Solution Overview
Problem
Existing contact lenses often fail to provide optimal wearing comfort due to uniform surface hardness, which can lead to discomfort and irritation.
Innovation Solution
A contact lens design with a softer posterior surface than anterior surface, achieved by varying the surface modulus through a method involving hydrogel layers with different indentation depths and stiffness, enhancing comfort by mimicking the eye's natural surface texture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If uniform surface hardness is used in contact lenses, then manufacturing is simpler and structural integrity is maintained, but wearing comfort deteriorates due to friction and irritation
Solution Approach 1:
The contact lens applies different surface modulus values to different regions: the posterior surface (contacting the eye) has a lower surface modulus (softer) while the anterior surface has a higher surface modulus (harder). This local differentiation optimizes comfort at the eye interface while maintaining structural integrity elsewhere.
Solution Approach 2:
The contact lens is segmented into distinct surface regions with different mechanical properties. The posterior surface is designed with softer characteristics while the anterior surface maintains harder characteristics, creating functional segmentation that addresses different requirements of each surface.
2Ease of operation
If the posterior surface is made softer to reduce friction, then wearing comfort improves, but the lens may become more susceptible to deformation
Solution Approach 1:
The softer posterior surface is localized only where needed for comfort, while the anterior surface maintains higher hardness and structural strength. This local quality differentiation allows the lens to be soft at the eye interface but rigid enough to maintain its shape and optical integrity.
Solution Approach 2:
The contact lens utilizes composite material structures or gradients that combine materials with different mechanical properties. The posterior surface incorporates softer materials or higher water content regions, while the anterior surface uses materials with higher mechanical strength, creating a composite structure that satisfies both comfort and strength requirements.
Data Source
AI summary
The invention is related to a contact lens, especially a SiHy contact lens, which comprises a lens bulk material covered with an outer surface hydrogel layer thereon and has a posterior surface and an opposite anterior surface. The outer surface hydrogel layer consists of an anterior outer hydrogel layer and a posterior outer hydrogel layer. A contact lens of the invention is characterized by having a difference in surface softness between its posterior (BC) and anterior (FC) surfaces.