A brain implant developed at Monash Vision Group (MVG) — a collaboration between Monash University, Alfred Health, MiniFAB, and Grey Innovation — could bring sight to up to 85% of clinically blind people, including patients affected by three of the most common untreatable causes of blindness: diabetic retinopathy, glaucoma, and macular degeneration. It could also help patients with an intact visual cortex, who have previously had normal visual development, and patients with acquired retinal, optic nerve, or ocular disease. MVG aims to deliver a commercially viable bionic eye system suitable for people with deteriorating vision with the following capabilities:
- Able to restore central vision without interfering with patients’ residual vision.
- Suitable for patients who have no vision and/or damaged optic nerves.
- Advanced neurosurgical techniques to implant the device.
- Able to adjust the bionic eye system after implantation to compensate for progressive deterioration of remaining natural vision.
Alternative bionic eye technologies often consist of an implant within the eye to stimulate the remaining parts of the retina. This approach offers exciting promise, but can be limited for the following reasons:
- Retinal stimulation cannot send visual signals to the brain if the optic nerves are damaged.
- People with partial vision loss risk losing vision in all regions due to retinal implant procedures
- The spatial resolution possible with retinal stimulation is limited in the central macular region of vision.
In contrast, MVG's direct-to-brain bionic eye system will combine state of the art digital and biomedical technology with consumer-friendly glasses. Using standard neurosurgery techniques, a small area of the skull will be temporarily removed. A sterile, biologically inert chip will be placed directly on the surface of the visual cortex of the brain. The small area of the skull will then be replaced and eventually heal, providing a natural barrier to protect against infection. A digital camera embedded in the glasses will capture images. As the patient's head turns, the glasses turn as well. Digital processors will modify the images captured by the camera; a wireless transmitter will then present the image that the patient is “looking at” to a chip that has been implanted at the back of the brain. Algorithms will transform the camera image data to a pattern that transmits to micro-sized electrodes on the brain implant with an appropriate voltage, current, and timing to stimulate the visual cortex of the brain. The chip will then directly stimulate the visual cortex of the brain with electrical signals using an array of micro-sized electrodes, and the brain will learn to interpret these signals as sight.
With many conditions, patients gradually lose sight in some areas of their visual field but not others. As the MVG approach does not require eye surgery, the researchers believe that existing sight will be retained and supplemented with the direct-to-brain bionic eye.
The exact effectiveness of the restored sight will be determined through research and development programs. This is likely to vary strongly between patients depending on their medical history and individual conditions. MVG is aiming to conduct the first patient tests by 2014.
The system will be designed to enable continual external adjustment by the patient's clinician, without the need for further surgery. As the patient gets older and residual natural vision continues to deteriorate, the camera and digital processor will be adjusted to compensate. The patient will continue to use what remains of his or her natural vision, with the bionic eye supplementing vision in those areas that are deteriorating.