- A newly published Cell paper (DOI: 10.1016/j.cell.2025.04.019) demonstrates “near-infrared spatiotemporal color vision” in humans using upconversion contact lenses (UCLs) that convert 980 nm light into visible green light via lanthanide nanoparticles, allowing wearers to perceive NIR patterns even with eyes closed.

- The lenses alone provide coarse temporal and quadrant-level perception; to reach fine spatial resolution (~65 cycles/degree, matching normal human acuity), the team added a wearable eyeglass system that projects structured NIR patterns directly onto the retina.

- Participants could reliably discriminate the direction of moving NIR gratings and recognize flicker frequencies, showing that the technology can extend human vision into a normally invisible spectral band without bulky external cameras.

- Optical limitations arise because up-converted light scatters before entering the eye, blurring spatial detail; the authors propose future fixes such as nanoparticles engineered to emit only in the forward direction or embedding micro-optical fiber channels inside the lens to guide light straight to the retina.

- A practical manufacturing idea floated in the channel suggests aligning encapsulated nanoparticles with an electric field so each capsule acts as a tiny directional antenna: a reflective dish with the upconversion particle at its focus and a small aperture to admit incoming IR light, potentially restoring sharp imagery without external optics.