India could be the next destination for clinical trials for the artificial retina referred to as the retinal prosthesis or bionic eye developed by Texas Instruments Incorporated (TI), a world leader in analog, signal processor and Microcontroller (MCU) technologies.
This artificial retina is recommended for patients suffering from Retinitis pigmentosa and macular degeneration which develop gradually and eventually results in total blindness.
Dr Rajat Agrawal, professor, University of Southern California, who has been working with TI for the development of bionic eye stated that extensive studies carried out in the US have indicated that the bionic eye can help such affected people see again.
The retinal prosthesis has the potential to treat blinding diseases of the outer retina, such as age-related macular degeneration and retinitis pigmentosa. Although photoreceptors are significantly degenerated by these diseases, the inner retinal cells are still present and can be electrically activated to produce the sensation of light.
Dr Agrawal who was in India for the 11th TI Developer meet in Bangalore has been involved in the Artificial Retinal Implant project, which aims at developing a complex artificial epiretinal devices to provide veision to blind people.
In the 16-electrode ARGUS I clinical trial, which was the first generation retinal prosthesis, retinal prostheses were implanted in six subjects with advanced retinitis pigmentosa with bare or no light perception. The US FDA granted an investigational device exemption and USC institutional review board approved the study protocol.
Subjects were screened using visual psychophysics, electrophysiology, ophthalmic photography, and scanning laser ophthalmoscopy. Implants consisted of an extraocular microelectronic device and an intraocular electrode array, connected by a multiwire cable. The electrode array is a 4x4 grid of platinum electrodes embedded in silicone rubber. Electrodes are wirelessly activated using an external system. The external system is controlled via a computer interface or a head mounted video camera. These 6 subjects have been implanted for more than five years. Perception thresholds of less than 20 microAmperes (1 millisecpulses) have been routinely recorded on multiple electrodes. Performance using the head mounted video camera suggests that subjects are capable of interpreting patterned electrical stimulation. Subjects can identify objects from a set and detect the direction of a moving bar.
The second-generation ARGUS II clinical trial is on-going, where a 60-electrode device has been implanted in 10 patients in the United Stated, five in Europe and two in Mexico. Using data generated by these clinical trials, considerable progress has been made towards a higher resolution device targeting 1000 electrodes, which simulations predict can restore face recognition and mobility to blind individuals.
The bionic eye implant is meant for blind people whose light receiving cells of the retina are damaged. The prosthetic device functions as a cornea, directing the light into the interior of the eye. Once readily available, it will have a huge market.
The trials are expected to take off in India in 2009 end and leading ophthalmology care hospitals could probably undertake the human studies, added Dr Agrawal.
According to the World Health Organization estimates around 37 million globally are blind and 124 million suffer from some kind of visual impairment. It is also estimated that without proper interventions, the number of people who are blind are likely to increase to 75 million by 2020.