Retinal Prosthesis Electrode Array Segmentation
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Solution Overview
Problem
Existing retinal prostheses are bulky and unable to provide adequate simulated vision for the visually impaired, with challenges in achieving high-resolution stimulation and efficient implantation, particularly in replicating the natural resolution and curvature of the retina.
Innovation Solution
A retinal prosthesis design featuring a high-resolution electrode array implanted near the fovea using photolithography and a lower-resolution array molded in silicone placed around the periphery, with external implantation to reduce the number of wires through the sclera and accommodate natural curvature, supported by a flexible silicone elastomer strap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single integrated electrode array is used in existing retinal prostheses, then the device structure is simplified, but the manufacturing precision and ability to replicate natural retinal resolution are compromised
Solution Approach 1:
The electrode array is divided into multiple independent segments with different resolutions. A first electrode array provides high-resolution stimulation for the foveal region, while a second electrode array provides lower-resolution stimulation for peripheral regions. This segmentation allows each array to be optimized for its specific function, achieving high manufacturing precision without requiring a single complex integrated structure.
2Reliability
If electrodes are implanted through the sclera, then electrical stimulation of the retina is achieved, but the number of wires increases and mechanical stress on the implant increases
Solution Approach 1:
The first and second electrode arrays are electrically connected through a common return electrode. This merging of electrical pathways reduces the total number of separate wire connections needed through the sclera, thereby reducing mechanical stress on the implant while maintaining effective electrical stimulation of retinal neurons.
3Measurement precision
If a high-resolution electrode array is implanted near the fovea, then artificial vision quality is improved, but the number of wires and device bulkiness increase
Solution Approach 1:
The prosthesis employs local quality by providing high-resolution electrode density in the foveal region where visual acuity is most critical, while using lower-resolution electrodes in peripheral regions. This localized optimization achieves high measurement precision for central vision without requiring high-resolution electrodes throughout the entire retinal surface, thereby reducing overall device bulkiness.
4Reliability
If multiple wires are passed through the sclera for electrode connections, then electrical connectivity is ensured, but heat dissipation efficiency decreases and mechanical stability is compromised
Solution Approach 1:
Multiple electrode arrays are electrically connected through a common return electrode pathway, merging the electrical connections. This reduces the number of separate wires that must be passed through the sclera, improving heat dissipation efficiency by reducing thermal load from multiple wire interfaces while maintaining reliable electrical connectivity through the consolidated return path.
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
This design provides improved manufacturability and stability, allowing for efficient heat dissipation and reduced mechanical stress, enabling effective stimulation of retinal neurons for artificial vision, while accommodating the natural curvature and resolution of the retina.
Implementation Method 1
Neural tissue can be artificially stimulated and activated by prosthetic devices that pass pulses of electrical current through electrodes on such a device. The passage of current causes changes in electrical potentials across visual neuronal membranes, which can initiate visual neuron action potentials
Implementation Method 2
This design provides improved manufacturability and stability, allowing for efficient heat dissipation
Data Source
AI summary
The artificial percept of light may be created by electrically stimulating the neurons of the retina. While a photolithographed array internal to the retina provides superior resolution, an array external to the retina provides easier implantation and improved manufacturability. Therefore it is advantageous to supply a high-resolution electrode array internal to the sclera, near the fovea and a lower-resolution electrode array external to the sclera near the periphery of the retina. It is advantageous to encourage current to flow through the retina by providing a physically separate and distinct electrode array and return electrode. The high-resolution electrode array and lower-resolution electrode array may be return electrodes for the other, or completely separate return electrodes may be provided.