Visual and Non-Visual Navigation in Blind Patients with a Retinal Prosthesis

Area of Science:

• Neuroscience
• Vision Science
• Rehabilitation Engineering

Background:

• Normal vision enables combining visual landmarks and self-motion for precise navigation.
• Retinal prostheses aim to restore some visual function for individuals with blindness.
• The utility of prosthetic vision in complex spatial tasks remains under investigation.

Purpose of the Study:

• To investigate if individuals with blindness using the Argus II retinal prosthesis can integrate prosthetic vision with non-visual cues for improved navigation.
• To compare navigational performance between prosthesis users and sighted controls under varying visual conditions.

Main Methods:

• Four patients with long-term blindness implanted with the Argus II retinal prosthesis participated.
• Navigation tasks (path reproduction, triangle completion) were performed with and without prosthetic vision.
• Control groups (age-matched and younger sighted individuals) used simulated reduced vision goggles.

Main Results:

• Control participants navigated more precisely with reduced vision compared to no vision.
• Argus II users showed no improvement in path reproduction with the prosthesis; two showed improvement in triangle completion.
• Patients demonstrated superior precision to controls when navigating without vision.

Conclusions:

• The Argus II retinal prosthesis may not provide sufficient visual reliability to enhance navigation in blind individuals.
• Learned reliance on non-visual senses may outweigh benefits from current prosthetic vision in spatial tasks.
• Further development is needed to improve the functional visual information provided by retinal prostheses for navigation.