Tear Shaping Contact Lens for Refractive Correction
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Solution Overview
Problem
Conventional contact lenses can cause complications such as stasis and entrapment of the tear film, leading to corneal epithelial waste accumulation, abrasion, and reduced oxygen availability, which can be toxic to the corneal epithelium, and they do not effectively address refractive corrections for astigmatism.
Innovation Solution
A contact lens design featuring a central opening or cavity that allows capillary action to form a meniscus of tears, with varying shapes and sizes to create a refractive effect, including concave and convex menisci for myopia and astigmatism correction, and includes features like non-circular openings, varying rim shapes, and partial depth cavities to enhance tear exchange and oxygen permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional contact lenses are used to achieve refractive correction, then optical correction is provided, but tear film stasis and entrapment occur leading to corneal epithelial waste accumulation and toxicity
Solution Approach 1:
The contact lens is segmented into multiple zones including a central optical zone, an intermediate zone, and a peripheral zone. This segmentation allows different regions to perform different functions: the central zone provides optical correction while the peripheral zones facilitate tear exchange and prevent waste accumulation, thereby resolving the contradiction between maintaining refractive correction and preventing corneal toxicity.
Solution Approach 2:
Different regions of the contact lens are designed with different properties: the central optical zone has specific refractive properties for correction, while the peripheral zones have enhanced tear exchange capabilities. This local differentiation allows the lens to simultaneously provide optical correction and prevent tear film stasis, resolving the harmful effects on corneal epithelium.
2Reliability
If conventional contact lenses are used for refractive correction, then optical power is achieved, but mechanical interaction causes corneal epithelial abrasion
Solution Approach 1:
The lens is divided into functional zones where the peripheral zones are designed to reduce mechanical interaction with the cornea. This segmentation allows the central zone to maintain optical correction while the peripheral zones minimize abrasion by facilitating tear flow and reducing direct contact pressure.
Solution Approach 2:
The intermediate zone acts as a mediator between the central optical zone and the peripheral tear exchange zone. This intermediate region helps distribute mechanical stresses and reduces direct mechanical interaction between the lens and corneal epithelium, thereby preventing abrasion while maintaining optical correction.
3Reliability
If conventional contact lenses are used to correct refraction, then optical correction is provided, but oxygen availability to the corneal epithelium is reduced
Solution Approach 1:
The contact lens is segmented into zones that facilitate oxygen transport. The peripheral zones are designed with enhanced permeability and tear exchange capabilities that allow oxygen to reach the corneal epithelium more effectively, while the central zone maintains optical correction. This segmentation resolves the contradiction between providing refraction correction and maintaining oxygen availability.
4Reliability
If rigid contact lenses are used to create a tear lens for refractive correction, then refractive power is enhanced, but the lens shape must maintain independence from corneal shape
Solution Approach 1:
The lens is segmented into a central optical zone and peripheral zones with different curvature characteristics. This segmentation allows the central zone to maintain its shape for optical correction while the peripheral zones adapt to the corneal shape to facilitate tear exchange, reducing the complexity of maintaining independent lens shape throughout the entire lens.
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 lens design reduces complications by forming a tear meniscus that contributes to refractive correction while minimizing contact lens-related issues, such as stasis and abrasion, and allows for effective correction of myopia and astigmatism through controlled tear shaping and exchange.
Implementation Method 1
The central opening is structured such that capillary action forms a meniscus of tears in the opening
Implementation Method 2
Contact lenses known to the Applicant achieve refractive correction because of the optical nature of an optically transparent, rigid, semi-rigid or flexible material that refracts light and thus alters the refraction of light striking the cornea
Data Source
AI summary
A lens for refractive tear shaping, including a curved lens body defining a central cavity indented into its posterior surface. The central cavity has a posterior facing tear shaping surface structured to form a tear lens within the central cavity. The central cavity is structured to define a tear lens within the central cavity by interaction between a tear film of the eye and the posterior facing tear shaping surface. The anterior curvature of the tear lens being dependent on the shape of the tear shaping surface.