Take-home message: One-year outcomes with a subretinal implant for patients blinded by retinitis pigmentosa demonstrated a marked improvement in visual capabilities.
Dresden, Germany—Early experience with a subretinal electronic chip (Alpha IMS, Retina Implant AG) shows it is safe and can restore useful vision to a majority of patients who are blind because of retinitis pigmentosa, said Helmut Sachs, MD.
The device received the CE mark for commercial use in Europe in July 2013, and a study to gain FDA approval in the United States is planned.
“Electronic implants are presently the only strategy that allows patients blind from hereditary retinal disease to regain some vision,” said Dr. Sachs, senior consultant and chairman, Department of Ophthalmology, Clinic Dresden-Friedrichstadt, Germany. “As one approach, the subretinal implant offers some advantages, and it has been associated with encouraging outcomes.
“Now, we look forward to assessing its stability and performance long term and to technical advances that will improve visual resolution and contrast vision to further increase the implant’s value to patients in daily life,” said Dr. Sachs, who is also an investigator in an ongoing multicenter study evaluating the subretinal implant.
How the device works
The subretinal chip is a 3- × 3-mm square containing 1,500 electrodes. It is implanted transchoroidally beneath the fovea and without any need for fixation.
“The subretinal chip replaces degenerated photoreceptors with microphotodiode arrays,” Dr. Sachs said. “Vision is restored by stimulating the ganglion cells because the inner retina is still intact in patients with retinitis pigmentosa even years after blindness occurs.”
The subretinal chip receives power inductively from a transmitter coil that is placed subdermally behind the ear. Originally the chip and transmitter coil were linked via a cable, but now the system features wireless power and signal transmission.