Enhanced Contact Lenses Enable Vision in Infrared Spectrum, Even in Darkness

Contact lenses enable users to perceive beyond the visible light spectrum, detecting infrared flickers even in darkness or with closed eyes.

The lenses incorporate engineered nanoparticles that absorb and convert infrared radiation, particularly within the near-infrared range of 800-1600 nanometers. This technology functions similarly to night vision equipment, allowing visibility in low-light conditions, but the contact lenses are significantly lighter and do not need any external power source.

“Contact lenses grant military personnel a modest, hands-free nighttime capability, overcoming the challenges posed by cumbersome night vision [goggles or scopes]” stated Peter Rentzepis from Texas A&M University, who is involved in related research employing the same nanoparticles (sodium fluoride, ytterbium, erbium) for eyeglass lenses.

The innovative wearables developed by Yuqian Ma from the China University of Science and Technology and his team have not yet achieved detailed night vision. This limitation occurs because they can solely detect “high-intensity narrowband LED” light sources, as noted by Rentzepis, without capturing the ambient infrared light.

“While it’s an ambitious study, contact lenses alone cannot be employed for reading in infrared or navigating dark paths,” explained Mikhail Kats, who is not associated with the research, at the University of Wisconsin-Madison.

In human-mouse studies, the contact lenses transformed an otherwise invisible flash of infrared light into what Kats describes as “a significant, colorful chunk of visible light.” These representations serve a purpose; for instance, MA and his team encoded and transmitted alphabetic characters by altering the frequency, quantity, and color of various light flashes.

This research builds upon previous studies where scientists directly injected nanoparticles into the eyes of mice to facilitate infrared vision. Wearable contact lenses present a “safer and more practical approach to human applications,” observes Rentzepis. However, he cautions that they still pose potential health and safety concerns, such as risks of thermal exposure from the photoconversion process or the leakage of nanoparticles into ocular tissues.