Feed: Slashdot
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Title: Infrared Contact Lenses Allow People To See In the Dark, Even With
Eyes Closed

Link: https://science.slashdot.org/story/25/05/23/0...

An anonymous reader quotes a report from Phys.Org: Neuroscientists and
materials scientists have created contact lenses that enable infrared vision
in both humans and mice by converting infrared light into visible light.
Unlike infrared night vision goggles, the contact lenses, described in the
journal Cell, do not require a power source -- and they enable the wearer to
perceive multiple infrared wavelengths. Because they're transparent, users
can see both infrared and visible light simultaneously, though infrared
vision was enhanced when participants had their eyes closed. [...] The
contact lens technology uses nanoparticles that absorb infrared light and
convert it into wavelengths that are visible to mammalian eyes (e.g.,
electromagnetic radiation in the 400-700 nm range). The nanoparticles
specifically enable the detection of "near-infrared light," which is infrared
light in the 800-1600 nm range, just beyond what humans can already see. The
team previously showed that these nanoparticles enable infrared vision in
mice when injected into the retina, but they wanted to design a less invasive
option. To create the contact lenses, the team combined the nanoparticles
with flexible, nontoxic polymers that are used in standard soft contact
lenses. After showing that the contact lenses were nontoxic, they tested
their function in both humans and mice. They found that contact lens-wearing
mice displayed behaviors suggesting that they could see infrared wavelengths.
For example, when the mice were given the choice of a dark box and an
infrared-illuminated box, contact-wearing mice chose the dark box whereas
contact-less mice showed no preference. The mice also showed physiological
signals of infrared vision: the pupils of contact-wearing mice constricted in
the presence of infrared light, and brain imaging revealed that infrared
light caused their visual processing centers to light up. In humans, the
infrared contact lenses enabled participants to accurately detect flashing
morse code-like signals and to perceive the direction of incoming infrared
light. An additional tweak to the contact lenses allows users to
differentiate between different spectra of infrared light by engineering the
nanoparticles to color-code different infrared wavelengths. For example,
infrared wavelengths of 980 nm were converted to blue light, wavelengths of
808 nm were converted to green light, and wavelengths of 1,532 nm were
converted to red light. In addition to enabling wearers to perceive more
detail within the infrared spectrum, these color-coding nanoparticles could
be modified to help color-blind people see wavelengths that they would
otherwise be unable to detect. [...] Because the contact lenses have limited
ability to capture fine details (due to their close proximity to the retina,
which causes the converted light particles to scatter), the team also
developed a wearable glass system using the same nanoparticle technology,
which enabled participants to perceive higher-resolution infrared
information. Currently, the contact lenses are only able to detect infrared
radiation projected from an LED light source, but the researchers are working
to increase the nanoparticles' sensitivity so that they can detect lower
levels of infrared light.

Read more of this story at Slashdot.

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