New Contact Lenses Let You See Infrared Light

Such lightwaves exist beyond our natural field of vision, but with these contacts you can see infrared light even with your eyes closed

Hiya!

The electromagnetic spectrum, comprising various types of electromagnetic radiation, has fascinated me since childhood. Even now, as an adult, it blows my mind that everything I can see, every hue I can distinguish, makes up only a fraction of the spectrum.

Meanwhile, the rest of the spectrum — which includes radio waves, microwaves, infrared radiation, ultraviolet radiation, X-rays, gamma rays, and more — exists all around us, yet we can’t see it. Even right now, as you read this, a mirage of invisible electromagnetic waves are swirling around you, and you’d never know it.

Of course, being Human, we’ve worked tirelessly to invent technology capable of capturing the rest of the electromagnetic spectrum and translate it into something we can understand. And now, a group of Chinese scientists has developed contact lenses that essentially provide the wearer with infrared vision, which wearers perceive as layered on top of their typical vision.

Human Vision

As I mentioned, we humans can only see a fraction of the electromagnetic spectrum. This is because the electromagnetic radiation that makes up the spectrum comes in various wavelengths. In order from shortest to longest, the spectrum includes cosmic rays, gamma rays, X-rays, ultraviolet radiation, visible light, infrared radiation, microwaves, radio waves, and the broadcast band.

The rainbow of colors our human eyes detect (visible light) ranges from just 380 to 700 nanometers (nm) in length. For reference, a single red blood cell is approximately 7,000 nm across.

As a result, we can see less than one-hundredth of a percent of the electromagnetic spectrum. If you’re like me, it’s challenging to comprehend just how little this is, but the image below helped me grasp it.

Image Source: Statement by the University of Science and Technology of China

As you can see, our visual range is sandwiched between Ultraviolet (UV) light, which has wavelengths that are just a little too short for us to see, and Infrared light, which has wavelengths just a bit too long for us to see. However, many other animals can see them.

For instance, birds, reindeer, mice, and bees can all perceive ultraviolet wavelengths. Meanwhile, vampire bats, along with many reptiles and insects, can detect infrared light, also known as thermal radiation, which aids them in their hunting but likely isn’t sensitive enough to form images.

And for this article, it’s the infrared waves that I’ll be focusing on.

Infrared Light

The infrared spectrum is broad in itself, with wavelengths ranging from around 700 nanometers (nm) to 1 millimeter (mm) and is split into three categories — near, mid, and far infrared.

As Yuqian Ma, ophthalmologist, neuroscientist, and researcher at the University of Science and Technology of China (USTC) in Hefei, and lead researcher of the study I’ll tell you about next, told Ian Sample of The Guardian:

“Over half of the solar radiation energy, existing as infrared light, remains imperceptible to humans.”

Since some infrared light (near-infrared) exists just beyond the boundaries of our visual range, experts have already developed technology, such as night vision goggles, that converts the infrared waves into ones we can perceive.

On one hand, night vision goggles sufficiently allow us to expand our natural range of vision into the infrared range. But on the other hand, they’re also bulky, require a power source to function, and capture only the upper range of the infrared light spectrum, which is emitted as heat by objects.

However, Ma and his team have now elevated this concept by developing contact lenses that enable wearers to see infrared light, even with their eyes closed.

New Invention

Ma has dedicated years to finding a more efficient way for us to perceive the infrared spectrum without the need for bulky equipment. To achieve this, he and his team recently developed contact lenses that absorb infrared light and re-emit it as red, green, or blue light waves that we can see — and they achieved this by using upconversion nanoparticles.