Estimating Phosphene Locations Using Eye Movements of Suprachoroidal Retinal Prosthesis Users

Area of Science:

• Biomedical Engineering
• Neuroscience
• Ophthalmology

Background:

• Accurate spatial encoding is crucial for visual prostheses to restore vision.
• Phosphene mapping, identifying perceived light locations, is essential for calibrating these devices.
• Current methods, like finger-based mapping, can be time-consuming and subjective.

Purpose of the Study:

• To demonstrate and evaluate phosphene mapping using eye movements (gaze-based) for a retinal implant.
• To compare gaze-based mapping with conventional finger-based mapping and retinotopic electrode positions.
• To assess the accuracy and feasibility of gaze-based phosphene mapping in retinal prosthesis recipients.

Main Methods:

• Three participants with suprachoroidal retinal implants participated in the study.
• Phosphene locations were identified using both finger-based and gaze-based (eye movement) methods.
• Procrustes analysis was used to compare measured phosphene locations with expected retinotopic electrode positions.

Main Results:

• Finger-based mapping showed spatial compression of phosphenes in all subjects but maintained retinotopic order.
• Gaze-based mapping yielded results similar to expected locations in two out of three subjects.
• One subject could not generate a coherent gaze-based map, potentially due to indistinct phosphenes.

Conclusions:

• Gaze-based phosphene mapping is a feasible alternative to finger-based methods for retinal implants.
• The effectiveness of gaze-based mapping varies among individuals, with some unable to produce coherent maps.
• This technique shows promise for improving the calibration and spatial encoding capabilities of visual prostheses.