In a significant breakthrough for medical science, researchers from Stanford University have created a wireless ocular prosthesis that successfully restores vision in individuals with irreversible blindness. This innovative device, named Prima, has shown promising results in clinical trials involving 38 patients suffering from geographic atrophy, a late stage of age-related macular degeneration (AMD).
All participants in the study were over the age of 60 and had been dealing with this previously untreatable condition, which progressively worsens vision. At the start of the clinical trial, these patients retained only limited peripheral vision. After a year of using the Prima device, 27 out of 31 participants regained the ability to read letters, numbers, and words with the previously blind eye. The findings have been detailed in the New England Journal of Medicine.
The Prima device comprises two main components. The first is an ultra-thin wireless microchip, measuring just 2 by 2 millimeters, implanted at the back of the eye through a vitrectomy. This surgical procedure involves removing the vitreous gel located between the lens and retina, allowing the chip to be placed directly under the center of the retina.
The second component is a pair of augmented reality glasses equipped with a small camera that captures images from the patient”s surroundings. These images are then projected in real-time onto the microchip using infrared light. The chip, sensitive to this infrared light, substitutes for the damaged natural photoreceptors, converting the light signal into electrical stimuli that the retina can relay to the brain.
Importantly, the device operates on photovoltaic technology, requiring only light to generate electrical stimuli, eliminating the need for an external power source. This sets it apart from other ocular prosthetics that require external wiring. The design also enables patients to utilize their natural peripheral vision alongside the central vision facilitated by the prosthesis, enhancing their navigation abilities.
Daniel Palanker, an ophthalmology researcher at Stanford University and one of the study”s authors, emphasized the significance of patients being able to simultaneously use both prosthetic and peripheral vision, stating, “This integration allows them to merge both types of vision and maximize their visual capabilities.”
Participants began using the augmented reality glasses approximately four to five weeks after the microchip was implanted. While some individuals were able to recognize patterns immediately, the majority saw improvements in visual acuity after several months of training, mirroring the experiences of other auditory implants developed to restore hearing.
Most patients have incorporated the prosthesis into their daily lives, using it to read books, food labels, and street or public transport signs. The glasses also come with adjustable contrast and brightness settings, along with a zoom feature that magnifies images up to twelve times. According to the researchers, about two-thirds of participants reported high levels of satisfaction with the device.
Looking ahead, the Prima implant currently allows users to see in black and white, lacking intermediate shades. Researchers are actively working on software that would enable users to distinguish a full range of grays. “While the primary desire of participants is to read, the next is facial recognition, which requires software capable of recognizing gray tones,” explained Palanker.
The team is also exploring ways to enhance the chip”s resolution, improve the design of the glasses, and adapt the device for other types of blindness caused by photoreceptor loss. This advancement is the culmination of decades of research, prototype development, and animal testing.
