Miniature video camera used in first retinal prosthesis
Second Sight Medical Products has announced the first implant and successful activation of its Argus II retinal prosthetic in a dry age-related macular degeneration (AMD) patient.
The device uses a miniature video camera and electrodes to stimulate retinal receptors.
Second sight develops, manufactures and markets implantable visual prosthetics that restore some useful vision to blind patients. The implant of the Argus II is part of a feasibility study which aims to evaluate the safety and utility of the system in individuals with late-stage dry AMD, a condition that severely affects their central vision.
Dry AMD usually develops slowly and causes gradual loss of central vision. While dry AMD also affects the peripheral vision over time, it rarely results in loss of vision across the entire visual field. There are currently very limited approved treatment options for dry AMD.
Second Sight's Argus II System provides electrical stimulation that bypasses the defunct retinal cells and stimulates remaining viable cells inducing visual perception in individuals with severe to profound Retinitis Pigmentosa (RP).
The Argus II works by converting images captured by a miniature video camera mounted on the patient's glasses into a series of small electrical pulses, which are transmitted wirelessly to an array of electrodes implanted on the surface of the retina. These pulses are intended to stimulate the retina's remaining cells, resulting in the perception of patterns of light in the brain. The patient then learns to interpret these visual patterns, thereby regaining some visual function.
The implant was performed at the Manchester Royal Eye Hospital in the United Kingdom by Dr Paulo Stanga, consultant ophthalmologist and vitreoretinal surgeon at the Manchester Royal Eye Hospital, Professor of ophthalmology and retinal degeneration at the University of Manchester.
The device was activated approximately two weeks after implantation, and initial reports confirm that the subject is receiving some useful vision from the Argus II system. The Argus II has already been tested and approved in the United States and Europe for individuals with Retinitis Pigmentosa (RP) and outer retinal degeneration, respectively.
‘Retinal implants for individuals with AMD may restore some useful vision in their central visual field, which is non-functional due to degeneration of the photoreceptors. The goal in restoring this central vision is to provide individuals with AMD more natural vision and ultimately improve their independence and quality of life,’ said Stanga. ‘This is totally groundbreaking research, where positive results from the study could provide advanced dry AMD patients with a new alternative treatment.’
Eligibility for this study includes patients 25 to 85 years of age with advanced dry AMD, some residual light perception, and a previous history of useful form vision. Study subjects will be followed for three years to evaluate safety and utility of the Argus II system on visual function. Pending positive study results, the Second Sight plans to conduct a larger study to support market approvals. It is estimated that two million individuals worldwide are legally blind due to AMD and 375,000 people are blinded by RP.
Second Sight CEO, Dr Robert Greenberg, said: ‘We are very excited to begin such an important study for this patient population and to have the opportunity to help a great deal more people living with blindness. Though it is obviously still early in this clinical trial, we are very encouraged by these initial results.’