Simulated prosthetic visual fixation, saccade, and smooth pursuit

Area of Science:

• Biomedical Engineering
• Neuroscience
• Ophthalmology

Background:

• Electronic vision prostheses aim to restore sight for individuals with blindness.
• Simulated prosthetic vision using phosphene arrays allows for controlled experimental investigation.
• Assessing visual tracking functions like fixation, saccade, and smooth pursuit is crucial for prosthesis development.

Purpose of the Study:

• To evaluate the impact of an image analysis technique on simulated prosthetic vision tracking.
• To quantify improvements in visual fixation and smooth pursuit accuracy with the technique.
• To explore the potential of this approach for enhancing electronic vision prosthesis functionality.

Main Methods:

• Administered a visual tracking task to 20 subjects using simulated prosthetic vision (phosphene array).
• Collected 3 hours of data per subject over 10 visits, assessing fixation, saccade, and smooth pursuit.
• Developed and applied an image analysis technique involving overlapping Gaussian kernels.

Main Results:

• The image analysis technique improved fixation and pursuit accuracy by 35.8% and 6.8% respectively (8.3 and 3.3 min of visual arc).
• Accuracy improvements were observed for inter-phosphene spacing of 1.9 degrees.
• The technique assisted fixation and pursuit but not saccade accuracy, reducing required phosphene array movement.

Conclusions:

• An iterative, experimental approach to image analysis can enhance electronic vision prosthesis function.
• The demonstrated technique represents a foundational step towards improved visual function for implanted patients.
• Further development of image analysis is essential for optimizing prosthetic visual performance.