Over the past decade, reversing blindness has gone from fantasy to reality — but the available treatments are few, and often prohibitively expensive. A team of Chinese scientists hopes to change that, however, with the advent of a potential cure for hereditary and age-related blindness at an unprecedented low cost.
Researchers from Fudan University in Shanghai successfully restored vision in blind mice by implanting artificial photoreceptors directly into their eyes, according to a paper published Tuesday in Nature Communications, a scientific journal under Nature. Made of titanium dioxide nanowires coated with gold nanoparticles, the photoreceptors generate an electric current when exposed to light, which in turn stimulates nearby neurons to restore the visual response.
“Nanomaterials are very thin, and ocular implantation surgeries are highly practical in clinical contexts,” said Zhang Jiayi, a corresponding author on the paper and a lead researcher at Fudan’s State Key Laboratory of Medical Neurobiology. “As such, the application of this research on the blind will be simple and convenient,” she told Sixth Tone.
The procedure will target degenerative eye disease, a previously untreatable visual impairment caused by the deterioration of light-sensing nerve tissue at the back of the eye. Worldwide, some 25 million people — including 10 million in the United States — are affected by age-related macular degeneration, the primary cause of visual deficiency in industrialized countries.
An illustration shows how nanowire arrays restore vision in blind mice. Courtesy of Zhang Jiayi
The use of gene therapies, stem cell treatments, and artificial retinas to restore sight in people with visual impairments has seen considerable progress over the past two decades. However, the currently available treatments apply only to certain types of blindness affecting relatively few people, and are often expensive.
The U.S. Food and Drug Administration approved the world’s first artificial retina in February 2013, yet the $100,000 device — which includes special sunglasses with a built-in video camera — is only applicable to a rare type of blindness that affects just 10,000 people in the U.S. In January of this year, meanwhile, an American company offered the country’s first approved gene therapy to cure a rare inherited retinal disease for a price of $850,000.
According to Zhang, the team’s artificial photoreceptors cost as little as 1 yuan ($0.16) to produce, and do not require batteries or electronic devices as other ocular prostheses do.
The Chinese researchers’ five-month in vivo mouse implantation experiment has also reported reactions to certain colors — a never-before-seen outcome in previous experiments with retina-nanowire interfaces, which only resulted in recovered perception of light and dark.
Two days after performing the hourlong surgeries, the team detected visual responses in the mice. Even totally blind animals had their vision restored through implantation, Zhang said, adding that if the same procedure were applied to humans, it would mainly target those with macular degeneration — rather than a small pool of patients with rarer conditions.
The team is still working to improve the implanted mice’s perception of red light and dim light. Eventually, Zhang said, they hope their artificial photoreceptors “can reach a sensitivity similar to that of a human retina.”
Editor: David Paulk.
(Header image: A mouse peers over the gloved hand of a lab technician at the Jackson Laboratory in Bar Harbor, Maine, U.S., Jan. 24, 2006. IC)