Blind animals regain the ability to sense light with experimental eye drops

Blind mice that had lost the ability to distinguish light from darkness began avoiding brightly lit areas after receiving experimental eye drops. The response suggested that the animals had regained a limited ability to sense light.

A team led by the Institute for Bioengineering of Catalonia developed the treatment for degenerative eye diseases, including age-related macular degeneration and retinitis pigmentosa. These conditions gradually damage the cells responsible for detecting light.

Rather than attempting to repair photoreceptor cells that had already died, the researchers used light-sensitive molecules to take over part of their role. When exposed to visible light, the molecules change shape and stimulate surviving retinal nerve cells to transmit signals.

Some of the compounds can be delivered directly into the eye without gene modification or an implanted device. The researchers described the approach as a “molecular prosthesis” for the visual system. They also observed the return of visual reflexes in zebrafish larvae.

The work followed more than a decade of development and appeared in the Journal of the American Chemical Society. It has not restored dead photoreceptor cells and remains at the animal-research stage. The team must still determine how long the effect lasts and whether long-term use is safe before human trials can be considered.