How did scientists partially restore a blind man’s sight?

Using a technique known as optogenetics, scientists were able to partially restore a blind man’s sight by essentially reprogramming certain cells within the eye. The 58-year-old man in the study lost his sight decades ago due to retinitis pigmentosa, an inherited eye disease that affects 1 in 4,000 people. The rods and cones in his eyes don’t function correctly or have died off, meaning that the retinas, which usually receive signals from the rods and cones and interpret them to tell your brain what you’re seeing, weren’t picking up any signals from them.

“Optogenetics is the science of taking non-light sensitive cells and introducing genes to them that make them light sensitive,” according to Philip Lewis, a biomedical engineer at Monash University. Through this process, the team was able to essentially reprogram cells in the patient’s retina to be sensitive to light. When wearing a specialized pair of goggles that turn the light hitting the eye monochromatic and project it onto the re-engineered retina cells, the man reported that he could see the white stripes of a crosswalk after a few months.

The man was able to see objects like a stapler and a notebook while wearing the goggles, but not without them. The team also noted that the resolution is nowhere near high enough for him to be able to distinguish a face or read a book. But it’s a significant first step toward “restoration of some basic levels of vision [that] could help blind patients navigate day-to-day tasks and greatly improve their quality of life,” said Raymond Wong, a stem cell biologist at the University of Melbourne who develops treatments for eye diseases. Wong was not a part of the study, but said he thought it had “very exciting results.”