Humans can now see in the dark -- and even with their eyes closed -- using nanotechnology contact lenses that turn invisible infrared light into visible images, according to a new study published in the journal Cell.

After first testing in mice, scientists from China and the University of Massachusetts Chan Medical School created contact lenses for humans infused with specialized "nanoparticles," thousands of times smaller than a grain of sand, that let people see in the dark and in foggy conditions.

These nanoparticles are scattered throughout the soft lens material, where they absorb infrared light and convert it into images the human eye normally can't see.

Gang Han, the study's lead author and a Ph.D.-level nanoparticle researcher at UMass Chan Medical School, told ABC News the lenses enhance how someone sees color.

"When wearing them, you still see everything normally," Hans said. "The lenses simply add the ability to see infrared images on top of what we already normally see."

Wearing the lenses, participants were able to recognize coded flashes of infrared light — similar to Morse code — identify basic shapes and patterns, and even distinguish colors in the infrared range, effectively adding a new dimension to human vision, Han explained.

They could even perceive the images with their eyes closed, thanks to the ability of infrared light to pass through eyelids, he said.

Humans can naturally see only visible light, a small slice of the full light spectrum that includes invisible wavelengths like ultraviolet and infrared. Night vision goggles can detect infrared light, but they're bulky, often need a power source, and usually show images in green or black and white, Han said.

"What's special about our contact lenses is that they let you see infrared light in color — like red, green and blue — so you can tell different things apart more easily," Han emphasized.

So far, the lenses have only been tested on a small group of individuals in China, all with normal vision.

Han said the researchers now need to test them in a more diverse population, including people with different vision capabilities.

"While we haven't specifically studied these lenses for people with vision impairments or eye diseases, this is an important area we hope to explore in the future," he said, adding that there needs to be further assessment to test their safety and spot any long-term effects to the eye.

Advances in nanotechnology could bring everyday benefits, especially for first responders.

"Our lenses help rescuers see clearly and navigate safely in dangerous environments like fires or dense fog," he said.

Doctors already use infrared technology to highlight tumors treated with special dyes visible to infrared cameras. Han noted that the new lenses could enhance this approach by allowing surgeons to see near-infrared signals directly in their line of sight, without needing to glance at separate monitors.

"This study opens the door to many exciting applications of wearable technology, potentially transforming how we see and interact with our environment, especially in challenging conditions," he said.

The study was supported by the Human Frontier Science Program and included collaboration with U.S. scientists.

Dr. Karen Tachi Udoh is an internal medicine resident at Johns Hopkins Hospital and a member of the ABC News Medical Unit.