The pursuit of curing blindness began in the early 1960s in England with the pioneering research of Dr. Giles Brindley. In 1968, he achieved a breakthrough by implanting an array of 80 stimulating electrodes onto the visual cortex of the right hemisphere in a blind volunteer. This experiment demonstrated that external visual information could be transmitted directly into the patient’s perception, enabling her to recognize simple patterns and letters formed by combinations of multiple phosphenes. Building on Brindley’s groundbreaking work, Dr. William Dobelle dedicated his career to advancing artificial vision, with the ultimate goal of developing a visual prosthesis capable of restoring sight to the blind.
This project continued the pioneering work of Dr. Dobelle. Evaluating the performance of a visual prosthesis is critical for understanding its effectiveness in implanted patients. However, such evaluations involve significant risks, as electrical stimulation is applied directly to the visual nervous system. Prolonged stimulation can be unsafe for patients, making long-term testing impractical. To address this challenge, a visual prosthesis simulator can be used to achieve the same evaluation objectives while avoiding the risks associated with actual implanted devices
The simulator consists of a webcam, a laptop PC, and a head-mounted display (HMD). The webcam captures images and sends them to the laptop for processing. The laptop converts these images into phosphene dot patterns, which are then displayed on the HMD. Since the HMD also functions as a blindfold, the subject perceives only the phosphenes, replicating the visual experience of implanted blind patients. This allows sighted subjects to safely simulate and study the perceptual effects of a visual prosthesis. The simulator serves as a valuable tool for investigating both the efficacy and psychological impact of implanted vision prostheses. The simulator software was developed using LabVIEW.
The webcam captured images of objects, emphasizing high-contrast edges. The images were processed to extract these edges, which were then overlaid onto the phosphene maps obtained from one of Dobelle’s patients. Phosphenes located on or near the edges were selected, and the corresponding electrodes were stimulated. As a result, the phosphenes in the blind patient’s visual field formed an “image” representing the object.