Visual performance using a retinal prosthesis in three subjects with retinitis pigmentosa

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Neuroscience

Background:

• Retinitis pigmentosa (RP) causes progressive vision loss, often leading to blindness.
• Epiretinal prostheses offer a potential solution for restoring vision in RP patients.
• Understanding visual task performance is crucial for evaluating prosthesis efficacy.

Purpose of the Study:

• To evaluate the visual task performance of three blind subjects implanted with epiretinal prostheses.
• To assess the impact of different prosthesis settings on visual function.

Main Methods:

• Prospective investigational device exemption trial involving three subjects with RP and severe vision impairment.
• Implantation of a 4x4 electrode array epiretinal prosthesis.
• Visual function testing using a computer or head-worn camera, with masked assessment.
• Comparison of visual task scores against chance and evaluation of multipixel vs. single pixel settings.

Main Results:

• Subjects performed significantly better than chance in 83% of visual tasks.
• High accuracy in object localization, counting, and differentiation tasks (77-100%).
• Improved performance with multipixel settings in accuracy and reaction time compared to single pixel settings.

Conclusions:

• Epiretinal prostheses can facilitate basic visual task performance in individuals with RP-related blindness.
• Multipixel settings demonstrate a slight advantage over single pixel settings for visual prosthesis functionality.