Degenerative age-related vision loss is so common it would be easy to think it simply an unavoidable consequence of getting older. However, a number of innovative research projects have found ways to prevent, or at least slow, this seemingly inevitable process.
A great deal of age-related vision loss is related to a degradation of the retina, so many researchers have worked to develop different kinds of artificial retinas, using electrodes and sensors to replicate retinal functions. However, these prosthetic solutions are not ideal, requiring wiring, cameras and invasive surgery.
Another option to restore retinal function is by using specifically engineered nanoparticles to serve as light-sensitive conduits to retinal neurons. In a newly published study, researchers have demonstrated how conjugated polymer nanoparticles (P3HT-NP) can potentially spread broadly across the sub-retinal space and restore lost vision.
To test the efficacy and safety of these nanoparticles, the researchers looked to a rodent model of retinitis pigmentosa, a genetic condition causing gradual vision loss. Following just one sub-retinal injection of the experimental nanoparticles the researchers saw visual cortex activity and visual acuity return to levels similar to animals with healthy vision.
“In the model we studied, the nanoparticles stimulated the light-dependent activation of the intact internal retinal neurons, recovering visual responses with no inflammation of the retina,” says Mattia Bramini, a researcher working on the project. “Given that they achieved light sensitivity following a single injection, and with the potential for high spatial resolution, nanoparticles provide a new way forward in retinal prostheses, with potential applications not only in the case of retinitis pigmentosa but also in age-related macular degeneration.”
Bramini notes the way the nanoparticles disperse across the retina suggests the technology can restore a wide field of vision. This level of spatial resolution should be significantly greater than any currently available implant. Plus, a simple, and relatively non-invasive, surgical procedure means it would be easier to broadly deploy compared to other artificial retina technologies.
It is unclear how far from human testing the technology is, but the signs from these animal experiments are promising. At this stage the nanoparticles were shown to be safe and effective at restoring all signs of vision for at least eight months.
“This simplest of surgical operations with regard to retinal prosthesis implantation and broad retinal coverage, which potentially restores the entire visual field, opens up a whole new avenue for the clinical application of P3HT polymer nanoparticles in cases of degenerative blindness,” says Bramini.