The Appearance of Phosphenes Elicited Using a Suprachoroidal Retinal Prosthesis

Area of Science:

• Ophthalmology
• Neuroscience
• Biomedical Engineering

Background:

• Phosphenes are crucial for visual prosthetics to convey information to the blind.
• Understanding phosphene characteristics is key to developing effective bionic eye technology.

Purpose of the Study:

• To characterize the size, shape, and location of phosphenes generated by a suprachoroidal retinal prosthesis.
• To assess the potential of these phosphenes for visual restoration in patients with profound vision loss.

Main Methods:

• Three patients with retinitis pigmentosa received suprachoroidal electrode array implants.
• Electrical stimulation via biphasic pulses elicited phosphenes, which were then assessed for appearance, location, overlap, and recognition using psychophysics.

Main Results:

• Phosphenes were reliably elicited in all patients, exhibiting diverse shapes and sizes.
• Phosphene locations generally matched electrode positions, with overlap decreasing as electrode separation increased.
• Patients achieved varying recognition scores in identifying stimulated electrodes, indicating unique phosphene information.

Conclusions:

• The suprachoroidal space is an effective site for retinal stimulation via phosphene generation.
• Suprachoroidal implants can produce phosphenes with unique information, potentially enabling the creation of meaningful visual images for functional vision restoration.