The Perceptual Experience of Argus II Users

NCT05285618 | Completed Results FDA Device

• 1 other identifier: R00EY029329
• Study Type: interventional
• Target: 6
• Locations: 1 country
• Sites: 3

Brief Summary

This Basic Experimental Studies Involving Humans (BESH) study investigates phosphene perception and performance factors in blind participants implanted with the Argus II retinal prosthesis system. Using paired-electrode stimulation, we analyze how phosphene shape and number are influenced by neuroanatomical factors, stimulus parameters, and spatial offsets. Additionally, we examine the causes of high current thresholds and limited spatial resolution, which impede pattern vision in Argus II devices. This research aims to provide insights for optimizing stimulation strategies and improving retinal prosthesis design.

Conditions

Retinitis Pigmentosa

Outcome Measures

Primary Outcomes (1)

• Number of Phosphenes Perceived

  Number of phosphenes perceived in response to paired-electrode stimulation across 5 spatial distances and 7 temporal interpulse delays. Phosphenes are brief sensations of light or visual flashes that occur in the absence of an external light source. A response is counted as a phosphene if the participant reports any visual sensation consistent with a flash of light.

  during single-session testing

Study Arms (1)

Argus II users

EXPERIMENTAL

This Basic Experimental Studies Involving Humans (BESH) study investigates phosphene perception and performance factors in blind participants implanted with the Argus II retinal prosthesis system. Using paired-electrode stimulation, we analyze how phosphene shape and number are influenced by neuroanatomical factors, stimulus parameters, and spatial offsets. Additionally, we examine the causes of high current thresholds and limited spatial resolution, which impede pattern vision in Argus II devices. This research aims to provide insights for optimizing stimulation strategies and improving retinal prosthesis design.

Device: Argus II

Interventions

Argus II DEVICE

Participants used the Argus II retinal prosthesis system in both experiments to perform visual perception tasks.

Argus II users

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Subject must be at least 25 years of age;
• Subject has been implanted with the Argus II system;
• Subject's eye has healed from surgery and the surgeon has cleared the subject for programming;
• Subject has the cognitive and communication ability to participate in the study (i.e., follow spoken directions, perform tests, and give feedback);
• Subject is willing to conduct psychophysics testing up to 4-6 hours per day of testing on 3-5 consecutive days;
• Subject is capable of understanding patient information materials and giving written informed consent;
• Subject is able to walk unassisted.

You may not qualify if:

• Subject is unwilling or unable to travel to testing facility for at least 3 days of testing within a one-week timeframe;
• Sighted controls: Subject has a history of motion sickness or flicker vertigo
• Subject does not speak English;
• Subject has language or hearing impairment

Sponsors & Collaborators

• University of California, Santa Barbara: lead
• Johns Hopkins University: collaborator
• University of Michigan: collaborator
• National Eye Institute (NEI): collaborator

Study Sites (3)

University of California, Santa Barbara

Santa Barbara, California, 93106, United States

Location

Johns Hopkins University

Baltimore, Maryland, 21287, United States

Location

University of Michigan, Ann Arbor

Ann Arbor, Michigan, 48109, United States

Location

Related Publications (2)

• Yucel EI, Sadeghi R, Kartha A, Montezuma SR, Dagnelie G, Rokem A, Boynton GM, Fine I, Beyeler M. Factors affecting two-point discrimination in Argus II patients. Front Neurosci. 2022 Aug 24;16:901337. doi: 10.3389/fnins.2022.901337. eCollection 2022.

  PMID: 36090266 RESULT

• Hou Y, Nanduri D, Granley J, Weiland JD, Beyeler M. Axonal stimulation affects the linear summation of single-point perception in three Argus II users. J Neural Eng. 2024 Apr 8;21(2):026031. doi: 10.1088/1741-2552/ad31c4.

  PMID: 38457841 RESULT

MeSH Terms

Conditions

Retinitis Pigmentosa

Condition Hierarchy (Ancestors)

Eye Diseases, Hereditary; Eye Diseases; Retinal Dystrophies; Retinal Degeneration; Retinal Diseases; Genetic Diseases, Inborn; Congenital, Hereditary, and Neonatal Diseases and Abnormalities

Results Point of Contact

• Title: Michael Beyeler
• Organization: University of California, Santa Barbara

mbeyeler@ucsb.edu

(805) 893-4321

Study Officials

• Michael Beyeler, PhD

  University of California, Santa Barbara

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: Yes

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Study Record Dates

• First Submitted: February 4, 2022
• First Posted: March 17, 2022
• Study Start: January 11, 2022
• Primary Completion: August 31, 2023
• Study Completion: August 31, 2023
• Last Updated: January 1, 2025
• Results First Posted: January 1, 2025

Record last verified: 2024-12

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP
• Time Frame: Spring 2023 onward
• Access Criteria: Any researchers with a legitimate reason for wishing to re-analyze the data or compare them to study data collected in similar experiments

Locations

US (3)