Environmental Localization Mapping and Guidance for Visual Prosthesis Users

NCT04359108 | Completed Results FDA Device

• 2 other identifiers: IRB002289321R01EY029741-01A1
• Study Type: interventional
• Target: 26
• Locations: 1 country
• Sites: 2

Brief Summary

This study is driven by the hypothesis that independent navigation by blind users of visual prosthetic devices can be greatly aided by use of an autonomous navigational aid that provides information about the environment and guidance for navigation through multimodal sensory cues. For this study, the investigators developed a navigation system that uses on-board sensing to map the user's environment and compute navigable paths to desired destinations in real-time. Information regarding obstacles and directional guidance is communicated to the user via a combination of sensory modalities including limited vision (through the user's visual prosthesis), haptic, and audio cues. This study evaluates how effectively this navigational aid improves prosthetic vision users' ability to perform navigational tasks. The participants for this study include both retinal prosthesis users of the Argus II Retinal Prosthesis System (Argus II) and normally sighted individuals who use a virtual reality headset to simulate the limited vision of the Argus II system.

Conditions

Retinitis Pigmentosa; Visual Impairment; Visual Prosthesis

Keywords

Retinal Prosthesis; Argus II

Outcome Measures

Primary Outcomes (5)

• Duration of Time to Complete Navigational Tasks as Assessed by the Mean Duration of Travel in Seconds Normalized by the Nominal Path Distance in Meters

  Participants will be asked to complete the navigation tasks of crossing an obstacle field approximately 6 meters in length and navigating to a target destination located about 20 - 30 meters away. The normalized duration of time to complete each navigation task will be measured in seconds. To account for variability in the path distances of different trials, the measured time will be normalized by a reference (nominal) path distance in meters associated with the configuration of each trial. The mean normalized time across all trials will be computed for each intervention.

  Up to 7 minutes for each navigation task, on Day 1 or Day 2

• Distance Traversed to Complete Navigational Tasks as Assessed by the Mean Distance Traveled in Meters Normalized by the Nominal Path Distance in Meters

  Participants will be asked to complete the navigation tasks of crossing an obstacle field approximately 6 meters in length and navigating to a target destination located about 20 - 30 meters away. The normalized distance traversed to complete each navigation task will be measured. To account for variability in the path distances of different trials, the measured distance will be normalized by a reference (nominal) path distance in meters associated with the configuration of each trial. The mean normalized distance across all trials will be computed for each intervention.

  Up to 7 minutes for each navigation task, on Day 1 or Day 2

• Obstacle Avoidance While Completing Navigational Tasks as Assessed by the Mean Number of Contacts With Obstacles Normalized by the Nominal Path Distance in Meters

  Participants will be asked to complete the navigation tasks of crossing an obstacle field approximately 6 meters in length and navigating to a target destination located about 20 - 30 meters away. The number of contacts with obstacles encountered while completing each navigation task will be measured. To account for variability in the path distances of different trials, the number of contacts will be normalized by a reference (nominal) path distance in meters associated with the configuration of each trial. The mean normalized number of contacts with obstacles across all trials will be computed for each intervention.

  Up to 7 minutes for each navigation task, on Day 1 or Day 2

• Success in Completing Navigational Tasks as Assessed by the Mean Percentage of Trials Where Participants Successfully Reached the Intended Destination

  Participants will be asked to navigate to a target destination located about 20 - 30 meters away. We will measure success rate as the mean number of trials for which each participants successfully reached the intended destination divided by the total number of trials performed by that participant for each intervention.

  Up to 7 minutes for each navigation task, on Day 1 or Day 2

• Accuracy of Relative Distance Judgments as Assessed by the Percentage of Correct Responses

  Participants will be presented with two physical objects and asked to identify which of the objects is the nearer one after walking a controlled distance down a centerline oriented between the objects. We will measure accuracy as the percentage of correct responses (the total number of correct responses divided by the total number of trials times 100).

  Up to 60 seconds for each discrimination task, on Day 1 or Day 2

Study Arms (2)

Evaluation of normally sighted participants using a simulated visual prosthesis

EXPERIMENTAL

All normally sighted participants will be assigned to this arm of the study. This study group will perform all experiments using a virtual reality headset (Oculus Go) to simulate the limited vision of a retinal prosthesis system. This study group will include all interventions, including those that both match and exceed the visual performance of the Argus II system.

Device: Navigation system mode: Argus Vision; Device: Navigation system mode: Depth Vision; Device: Navigation system mode: Depth Vision with Haptic / Audio; Device: Navigation system mode: Haptic / Audio; Device: Navigation system mode: High Field-of-View Depth Vision; Device: Distance test vision mode: Low Resolution / Low Field-of-View; Device: Distance test vision mode: Low Resolution / High Field-of-View; Device: Distance test vision mode: High Resolution / Low Field-of-View; Device: Distance test vision mode: High Resolution / High Field-of-View

Evaluation of blind participants using the Argus II retinal prosthesis

EXPERIMENTAL

All blind participants who have been implanted with the Argus II Retinal Prosthesis System will be assigned to this arm of the study. This study group will be limited to performing a subset of the interventions including only those that do not exceed the visual performance of the Argus II system.

Device: Navigation system mode: Argus Vision; Device: Navigation system mode: Depth Vision; Device: Navigation system mode: Depth Vision with Haptic / Audio; Device: Navigation system mode: Haptic / Audio; Device: Distance test vision mode: Low Resolution / Low Field-of-View

Interventions

Navigation system mode: Argus Vision DEVICE

This intervention uses the navigational aid with the output sensory modalities configured as follows: * Vision: Argus mode * Haptics: none * Audio: none Since this mode only provides the standard Argus vision, it is equivalent to using the base Argus II system without the navigational aid.

Evaluation of blind participants using the Argus II retinal prosthesis; Evaluation of normally sighted participants using a simulated visual prosthesis

Navigation system mode: Depth Vision DEVICE

This intervention uses the navigational aid with the output sensory modalities configured as follows: * Vision: Depth mode (at Argus II resolution and field-of-view) * Haptics: none * Audio: none

Evaluation of blind participants using the Argus II retinal prosthesis; Evaluation of normally sighted participants using a simulated visual prosthesis

Navigation system mode: Depth Vision with Haptic / Audio DEVICE

This intervention uses the navigational aid with the output sensory modalities configured as follows: * Vision: Depth mode (at Argus II resolution and field-of-view) * Haptics: yes * Audio: yes

Evaluation of blind participants using the Argus II retinal prosthesis; Evaluation of normally sighted participants using a simulated visual prosthesis

Navigation system mode: Haptic / Audio DEVICE

This intervention uses the navigational aid with the output sensory modalities configured as follows: * Vision: none * Haptics: yes * Audio: yes Since this mode does not provide any visual feedback, it is equivalent to using navigational aid completely blind without a visual prosthesis.

Evaluation of blind participants using the Argus II retinal prosthesis; Evaluation of normally sighted participants using a simulated visual prosthesis

Navigation system mode: High Field-of-View Depth Vision DEVICE

This intervention uses the navigational aid with the output sensory modalities configured as follows: * Vision: High Field-of-View Depth mode (at twice the Argus II resolution and field-of-view along each dimension) * Haptics: none * Audio: none

Evaluation of normally sighted participants using a simulated visual prosthesis

Distance test vision mode: Low Resolution / Low Field-of-View DEVICE

This intervention performs the relative distance to two obstacles test with the user's vision output configured as follows: * Resolution: Low * Field-of-View: Low

Evaluation of blind participants using the Argus II retinal prosthesis; Evaluation of normally sighted participants using a simulated visual prosthesis

Distance test vision mode: Low Resolution / High Field-of-View DEVICE

This intervention performs the relative distance to two obstacles test with the user's vision output configured as follows: * Resolution: Low * Field-of-View: High

Evaluation of normally sighted participants using a simulated visual prosthesis

Distance test vision mode: High Resolution / Low Field-of-View DEVICE

This intervention performs the relative distance to two obstacles test with the user's vision output configured as follows: * Resolution: High * Field-of-View: Low

Evaluation of normally sighted participants using a simulated visual prosthesis

Distance test vision mode: High Resolution / High Field-of-View DEVICE

This intervention performs the relative distance to two obstacles test with the user's vision output configured as follows: * Resolution: High * Field-of-View: High

Evaluation of normally sighted participants using a simulated visual prosthesis

Eligibility Criteria

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

You may qualify if:

• Subject is 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;
• Subject does not speak English;
• Subject has language or hearing impairment.

Sponsors & Collaborators

• Johns Hopkins University: lead
• Carnegie Mellon University: collaborator
• National Eye Institute (NEI): collaborator

Study Sites (2)

Johns Hopkins Medicine - Wilmer Eye Institute

Baltimore, Maryland, 21205, United States

Location

Johns Hopkins Applied Physics Laboratory

Laurel, Maryland, 20723, United States

Location

Related Publications (1)

• Christie B, Norena Acosta N, Sadeghi R, Kartha A, Ewulum C, Caspi A, Tenore FV, Dagnelie G, Klatzky RL, Billings SD. Autonomous multisensory enhancement of a visual neuroprosthesis for navigation: Technical proof-of-concept with simulated prosthetic vision and single-subject case study of a visual prosthesis user. J Neural Eng. 2026 Jan 26. doi: 10.1088/1741-2552/ae3d67. Online ahead of print.

  PMID: 41587489 DERIVED

MeSH Terms

Conditions

Retinitis Pigmentosa; Vision Disorders

Condition Hierarchy (Ancestors)

Eye Diseases, Hereditary; Eye Diseases; Retinal Dystrophies; Retinal Degeneration; Retinal Diseases; Genetic Diseases, Inborn; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Sensation Disorders; Neurologic Manifestations; Nervous System Diseases; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Results Point of Contact

• Title: Seth Billings
• Organization: Johns Hopkins Applied Physics Laboratory

seth.billings@jhuapl.edu

240-228-7462

Study Officials

• Seth Billings, Ph.D.

  Johns Hopkins University

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: No
• Restrictive Agreement: No

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: April 21, 2020
• First Posted: April 24, 2020
• Study Start: March 16, 2021
• Primary Completion: September 30, 2024
• Study Completion: September 30, 2024
• Last Updated: March 10, 2025
• Results First Posted: March 10, 2025

Record last verified: 2025-02

Data Sharing

• IPD Sharing: Will not share

Locations

US (2)