Electrowetting Ophthalmic Device Replenishment Kit
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Solution Overview
Problem
Electrowetting ophthalmic devices face optical performance issues due to changes in osmolarity of tear fluid, leading to water loss and osmotic pressure gradients that affect lens shape and stability, especially in dry and windy conditions.
Innovation Solution
A system and kit for replenishing electrowetting ophthalmic devices with a solution having an osmolarity matching the initial osmolarity of the aqueous electrowetting solution, including surfactants to maintain optical clarity and prevent osmotic pressure distortions, using a container with agitators and heat sources to facilitate quick equilibrium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrowetting ophthalmic device uses a water-permeable lens material to allow tear fluid interaction, then comfort and oxygen permeability are improved, but water loss through osmosis increases and optical stability deteriorates
Solution Approach 1:
The patent applies parameter changes by adjusting the osmolarity of the aqueous electrowetting solution to be higher than that of tear fluid. This parameter adjustment creates an osmotic gradient that prevents water from the lens material from moving into the tear fluid, thereby reducing water loss and maintaining optical stability while preserving the benefits of water-permeable material.
2Reliability
If the osmolarity of the aqueous solution is increased to prevent water loss, then optical stability is improved, but comfort may deteriorate due to osmotic pressure differences
Solution Approach 1:
The patent applies local quality by creating different osmolarity conditions in different regions: the aqueous electrowetting solution has high osmolarity to prevent water loss and maintain optical stability, while a separate low-osmolarity rinsing solution is provided for contact with the eye to ensure comfort. This spatial differentiation of osmolarity properties resolves the contradiction between stability and comfort.
3Productivity
If a high osmolarity replenishing solution is used to maintain optical performance, then water replacement efficiency is improved, but user comfort worsens due to osmolarity mismatch with tear fluid
Solution Approach 1:
The patent applies segmentation by dividing the solution system into two distinct components: a high-osmolarity replenishing solution for efficient water and solute replacement, and a low-osmolarity rinsing solution for comfortable eye contact. This segmentation allows each solution to optimize its function without compromise, with the rinsing step serving as a transition between the high-osmolarity replenishment and the eye's tear fluid environment.
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 solution maintains stable optical performance by replenishing water and solutes, preventing osmotic pressure-induced distortions and ensuring comfort by using a high osmolarity solution that matches the initial osmolarity of the electrowetting device, with a rinsing solution to adjust osmolarity for user comfort.
Implementation Method 1
Certain ophthalmic devices provide accommodating changes in optical power based upon electrowetting. Such electrowetting generally operates by changing an apparent surface energy of a dielectric coating on an electrode from hydrophobic to hydrophilic when bias is applied, and vice versa. The apparent change in surface energy may cause an interface between two immiscible liquids of different refractive indices, such as an oil and a saline solution, to change shape, thereby providing a lensing effect.
Implementation Method 2
An osmolarity of an aqueous solution disposed within an electrowetting ophthalmic device is susceptible to change as an osmolarity of a tear fluid of an eye changes. Such changes in osmolarity of the aqueous solution can have deleterious effects on optical performance of the electrowetting ophthalmic device.
Data Source
AI summary
Systems and kits for replenishing an electrowetting ophthalmic device are described. In an embodiment, the system includes an electrowetting ophthalmic device including a lens material defining a cavity encasing an aqueous electrowetting solution; a replenishing solution having an osmolarity approximately equal to an osmolarity of the aqueous electrowetting solution; and a container shaped to carry the electrowetting ophthalmic device and the replenishing solution and to position the electrowetting ophthalmic device in contact with the replenishing solution when the electrowetting ophthalmic device and the replenishing solution are carried by the container. In an embodiment, the osmolarity of the aqueous electrowetting solution is higher than an osmolarity of a tear fluid of an eye.