Improving the spatial resolution of epiretinal implants by increasing stimulus pulse duration
Open accessAbstract
Retinal prosthetic implants are the only approved treatment for retinitis pigmentosa, a disease of the eye that causes blindness through gradual degeneration of photoreceptors. An array of microelectrodes triggered by input from a camera stimulates surviving retinal neurons, with each electrode acting as a pixel. Unintended stimulation of retinal ganglion cell axons causes patients to see large oblong shapes of light, rather than focal spots, making it difficult to perceive forms. To address this problem, we performed calcium imaging in isolated retinas and mapped the patterns of cells activated by different electrical stimulation protocols. We found that pulse durations two orders of magnitude longer than those typically used in existing implants stimulated inner retinal neurons while avoiding activation of ganglion cell axons, thus confining retinal responses to the site of the electrode. Multielectrode stimulation with 25-ms pulses can pattern letters on the retina corresponding to a Snellen acuity of 20/312. We validated our findings in a patient with an implanted epiretinal prosthesis by demonstrating that 25-ms pulses evoke focal spots of light.
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Using long and non-rectangular pulses mitigates elongated phosphenes by preferentially inducing network-mediated stimulation, resulting in a more localised activation.
“A way to mitigate this phenomenon is to use long and non-rectangular pulses that will preferentially induce network-mediated stimulation, resulting in a more localised activation [29,31].”
From Advances in visual prostheses: engineering and biological challenges (2022) · cites this paper as [31]
Increasing the pulse duration or using non-rectangular pulses facilitates network-mediated stimulation.
“Otherwise, increasing the pulse duration [31] or using non-rectangular pulses [29] facilitates network-mediated stimulation.”
From Advances in visual prostheses: engineering and biological challenges (2022) · cites this paper as [31]
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References 49 · Cited by 154
Research works printed but not linked: 1
- [9]Nanduri D thesis 2011 University of Southern California Los Angeles, CA
- Authors
- Weitz, A. C., Nanduri, D., Behrend, M. R., Gonzalez-Calle, A., Greenberg, R. J., Humayun, M. S., Chow, R. H., & Weiland, J. D.
- Affiliations
- University of Southern California (US)
- Second Sight Medical Products (US)
- Corresponding author
- Chow, Robert H.
- Weiland, James D.
- ORCID
- Venue
- Science Translational Medicine
- Published
- 2015-12-16
- Volume
- 7
- Issue
- 318
- Pages
- 318ra203-318ra203
- ISSN
- 1946-6234 (ISSN-L)
- 1946-6242
- PMC
- PMC4698804
- OpenAlex
- W2209723663
- Cited by
- 154
- References
- 49
- Citations by year
- 2026: 7 · 2025: 4 · 2024: 8 · 2023: 9 · 2022: 20 · 2021: 17 · 2020: 25 · 2019: 14 · 2018: 24 · 2017: 15 · 2016: 11
- FWCI
- 7.78
- Type
- journal article
- Language
- en
- Open access
- green
- www.ncbi.nlm.nih.gov
- Locations
- Science Translational Medicine (publishedVersion)
- PubMed (publishedVersion)
- Europe PMC (PubMed Central) (acceptedVersion)
- PubMed Central (acceptedVersion)
- Funders
- NSF (EEC-0310723)
- NIH (1R01EY022931, R01 GM85791)
- Beckman Initiative for Macular Research (157370747)
- Second Sight Medical Products Inc.
- NIH/National Center for Research Resources Southern California Clinical and Translational Science Institute (UL1TR000130)
- Topics
- Life Sciences › Neuroscience › Cellular and Molecular Neuroscience › Neuroscience and Neural Engineering
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Retinal Development and Disorders
- Life Sciences › Neuroscience › Cognitive Neuroscience › Tactile and Sensory Interactions
- Keywords
- epiretinal prosthesis, retinal prosthesis, retinitis pigmentosa, calcium imaging, spatial resolution, Snellen acuity
- MeSH terms
- Animals, Disease Models, Animal, Electric Stimulation, Evoked Potentials, Visual, Female, Humans, Microelectrodes, Miniaturization, Mutation, Synaptic Transmission, Phenotype, Phosphenes, Prosthesis Design, Retina, Retinal Ganglion Cells, Retinitis Pigmentosa, Rhodopsin, Time Factors, Transfection, Visual Pathways, Visual Perception, Biosensing Techniques, Genetic Predisposition to Disease, Rats, Long-Evans, Synaptic Potentials, Visual Prosthesis, In Vitro Techniques
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