Breakthrough Technique Restores Light Sensitivity In Damaged Retinas

April 30, 2008

Adapted from Novartis

The Friedrich Miescher Institute of the Novartis Research Foundation (FMI) today announced a novel technique that restores light sensitivity to previously unresponsive retinas in blind mice and, remarkably, produces light-induced behavioral change in mice with retinal damage. A study on the technique, published in Nature Neuroscience, indicates that the approach could be an alternative to surgical transplantation of electrode arrays.

"We are excited and encouraged by the results of the study, which open the way for clinical trials in humans," said Susan M. Gasser, Director of FMI. "The new technique developed at the FMI could revolutionize the way that retinitis pigmentosa and late-stage macular degeneration are treated, potentially eliminating the need for surgery."

The research team headed by Botond Roska of FMI, in collaboration with Connie Cepko of Harvard Medical School, adopted a novel approach by administering a gene of a light-activated protein from green algae to selected retinal cells. Their innovation involves the selective restoration of light sensitivity to circuits that respond to increases in light level and not those that respond to decreasing light levels. Treatment of blind mice with this technique enabled them to successfully perform visually guided behavioral tasks, an unprecedented result.

"Contrary to common belief, the retina is a complicated organ, with more than 50 types of neurons, performing sophisticated image processing tasks," says Botond Roska, lead investigator of the study at FMI. "By targeting a select population of these retinal neurons, we have been able to restore a meaningful response to light."

Today's research announcement is a major breakthrough in the possible treatment of one of the most devastating losses of human sensory conditions, and offers hope for treatment of a disease that frequently goes unnoticed until it has progressed past the point of treatability. Unlike other forms of retinal degeneration, retinitis pigmentosa initially inhibits night and peripheral vision, and therefore goes undetected by most afflicted with it until it has reached later stages, when it significantly limits all types of vision. The technique pioneered at FMI may one day also be used to treat late-stages of macular degeneration, in which photoreceptor function has been lost.

"This research opens a new plane of investigation, and offers hope for the millions affected by blindness due to retinitis pigmentosa and late-stage macular degeneration," said Jose Sahel, a leading ophthalmologist in the field of retinal degeneration. "We expect these findings will become increasingly valuable as the global population ages, given that these conditions are particularly acute among the elderly..."

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