Retinal implant wins FDA approval

The U.S. Food and Drug Administration (FDA) approved the Argus II retinal prosthesis system for use in the United States.

Mark Humayun, who holds joint appointments at the Keck School of Medicine of USC and the USC Viterbi School of Engineering, was a key member of the team that developed the device, which will be available to qualified patients at the Keck Medical Center of USC.

The Argus II, which received a unanimous recommendation for approval by the FDA’s Ophthalmic Devices Advisory Panel in September, restores some visual capabilities for patients whose blindness is caused by Retinitis Pigmentosa (RP), an inherited retinal degenerative disease that affects about 100,000 people nationwide.

“It is incredibly exciting to have FDA approval to begin implanting the Argus II and provide some restoration of vision to patients blinded from RP,” said Humayun, Cornelius Pings Professor of Biomedical Sciences and professor of ophthalmology, biomedical engineering, cell and neurobiology at USC. “In the patients that have been implanted to date, the improvement in the quality of life has been invaluable.

“The fact that many patients can use the Argus implant in their activities of daily living, such as recognizing large letters, locating the position of objects and more, has been beyond our wildest dreams,” Humayun added, “yet the promise to the patients is real, and we expect it only to improve over time.”

The Argus II, which is manufactured by Sylmar, Calif.-based Second Sight, was approved for use in Europe in 2011 and has been implanted in 30 patients in a clinical trial that began in 2007. Humayun performed many of the surgeries to implant the device.

The FDA approval paves the way for Second Sight to build a surgical network in the United States to implant the device, as well as to recruit hospitals to offer it, according to Robert Greensburg, president and CEO of the company.

The Argus II system uses a camera mounted on special glasses that sends a signal to an electronic receiver with 60 electrodes implanted inside the eye.

The receiver sends signals to the retina that travel through the optic nerve to the brain, where they can be interpreted as a visual picture. The researchers hope that one day the device can be improved to also help individuals with age-related macular degeneration, a similar but far more common disease.

Public inquiries regarding the Argus II can be directed to the Second Sight public information line at (855) 756-3703.

As the Argus II retinal implant is refined, it will be housed in the USC Institute of Biomedical Therapeutics. The new $60 million endowed interdisciplinary institute will bring together scientists, engineers and clinicians from around the world to study neural networks to develop bioelectronic solutions for the millions of people impacted by traumatic brain injury, stroke and debilitating eye diseases.

Totally blind mice get sight back

Totally blind mice have had their sight restored by injections of light-sensing cells into the eye, UK researchers report. The team in Oxford said their studies closely resemble the treatments that would be needed in people with degenerative eye disease. Similar results have already been achieved with night-blind mice.

Experts said the field was advancing rapidly, but there were still questions about the quality of vision restored. Patients with retinitis pigmentosa gradually lose light-sensing cells from the retina and can become blind. The research team, at the University of Oxford, used mice with a complete lack of light-sensing photoreceptor cells in their retinas. The mice were unable to tell the difference between light and dark.

Reconstruction

They injected “precursor” cells which will develop into the building blocks of a retina once inside the eye. Two weeks after the injections a retina had formed, according to the findings presented in the Proceedings of the National Academy of Sciences journal. Prof Robert MacLaren said: “We have recreated the whole structure, basically it’s the first proof that you can take a completely blind mouse, put the cells in and reconstruct the entire light-sensitive layer.”

Previous studies have achieved similar results with mice that had a partially degenerated retina. Prof MacLaren said this was like “restoring a whole computer screen rather than repairing individual pixels”. The mice were tested to see if they fled being in a bright area, if their pupils constricted in response to light and had their brain scanned to see if visual information was being processed by the mind.

Vision

Prof Pete Coffee, from the Institute of Ophthalmology at University College London, said the findings were important as they looked at the “most clinically relevant and severe case” of blindness. “This is probably what you would need to do to restore sight in a patient that has lost their vision,” he said.

However, he said this and similar studies needed to show how good the recovered vision was as brain scans and tests of light sensitivity were not enough. He said: “Can they tell the difference between a nasty animal and something to eat?”

Prof Robin Ali published research in the journal Nature showing that transplanting cells could restore vision in night-blind mice and then showed the same technique worked in a range of mice with degenerated retinas. He said: “These papers demonstrate that it is possible to transplant photoreceptor cells into a range of mice even with a severe level of degeneration. “I think it’s great that another group is showing the utility of photoreceptor transplantation.”

Researchers are already trialling human embryonic stem cells, at Moorfields Eye Hospital, in patients with Stargardt’s disease. Early results suggest the technique is safe but reliable results will take several years.

Retinal chips or bionic eyes are also being trailed in patients with retinitis pigmentosa.