Identification of Characters and Localization of Images Using Direct Multiple-Electrode Stimulation With a Suprachoroidal Retinal Prosthesis

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dc.contributor.authorShivdasani, Mohit
dc.contributor.authorSinclair, Nicholas
dc.contributor.authorGillespie, Lisa
dc.contributor.authorPetoe, Matthew
dc.contributor.authorTitchener, Samuel
dc.contributor.authorFallon, James
dc.contributor.authorPerera, Thushara
dc.contributor.authorPardinas-Diaz, Darien
dc.contributor.authorBarnes, Nick
dc.contributor.authorBlamey, Peter
dc.contributor.authorBionic Vision Australia Consortium
dc.date.accessioned2017-08-16T03:36:54Z
dc.date.available2017-08-16T03:36:54Z
dc.date.issued2017-08
dc.description.abstractPurpose: Retinal prostheses provide vision to blind patients by eliciting phosphenes through electrical stimulation. This study explored whether character identification and image localization could be achieved through direct multiple-electrode stimulation with a suprachoroidal retinal prosthesis. Methods: Two of three retinitis pigmentosa patients implanted with a suprachoroidal electrode array were tested on three psychophysical tasks. Electrode patterns were stimulated to elicit perception of simple characters, following which percept localization was tested using either static or dynamic images. Eye tracking was used to assess the association between accuracy and eye movements. Results: In the character identification task, accuracy ranged from 2.7% to 93.3%, depending on the patient and character. In the static image localization task, accuracy decreased from near perfect to <20% with decreasing contrast (patient 1). Patient 2 scored up to 70% at 100% contrast. In the dynamic image localization task, patient 1 recognized the trajectory of the image up to speeds of 64 deg/s, whereas patient 2 scored just above chance. The degree of eye movement in both patients was related to accuracy and, to some extent, stimulus direction. Conclusions: The ability to identify characters and localize percepts demonstrates the capacity of the suprachoroidal device to provide meaningful information to blind patients. The variation in scores across all tasks highlights the importance of using spatial cues from phosphenes, which becomes more difficult at low contrast. The use of spatial information from multiple electrodes and eye-movement compensation is expected to improve performance outcomes during real-world prosthesis use in a camera-based system. (ClinicalTrials.gov number, NCT01603576.).en_US
dc.description.sponsorshipSupported by the Australian Research Council through its Special Research Initiative in Bionic Vision Science and Technology awarded to Bionic Vision Australia, an NHMRC Project Grant 1082358 awarded to PJ Allen, and by the Bertalli Family and Clive & Vera Ramaciotti Foundations to the Bionics Institute; the Victorian Government through its Operational Infrastructure Program (Bionics Institute and the Centre for Eye Research Australia [CERA]); and a National Health and Medical Research Council, Centre for Clinical Research Excellence Award #529923 (CERA).en_US
dc.identifier.citationShivdasani, M. N., N. C. Sinclair, L. N. Gillespie, M. A. Petoe, S. A. Titchener, J. B. Fallon, T. Perera, D. Pardinas-Diaz, N. M. Barnes, and P. J. Blamey. 2017. Identification of Characters and Localization of Images Using Direct Multiple-Electrode Stimulation With a Suprachoroidal Retinal Prosthesis. Investigative Ophthalmology & Visual Science. 58(10): 3962-74.en_US
dc.identifier.issn0146-0404
dc.identifier.urihttp://repository.bionicsinstitute.org:8080/handle/123456789/252
dc.language.isoenen_US
dc.publisherIOVSen_US
dc.subjectRetinal prosthesesen_US
dc.subjectSuprachoroidalen_US
dc.subjectPsychophysicsen_US
dc.subjectRetinitis pigmentosaen_US
dc.subjectElectrical stimulationen_US
dc.titleIdentification of Characters and Localization of Images Using Direct Multiple-Electrode Stimulation With a Suprachoroidal Retinal Prosthesisen_US
dc.typeArticleen_US
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