A scratched lens can mean an expensive replacement, but the UV light-activated hydrogel can repair these small imperfections in under an hour.

The technology also offers greater durability and an antibacterial coating to create a robust and resistant, superior contact lens.

Researchers Jung-Hyun Choi and Byung-Ki Cho used the already widely-employed hydrogel to create their new prototype contact lenses while redesigning the complex polymer structure. Through a process known as disulfide exchange, UV light at a wavelength of 365 nanometers causes sulfur bonds in the gel to temporarily break apart and reconnect with neighboring atoms.

Before and after photos released in a study presenting their invention show how these new connections equate to a repaired scar on the surface of the lens.

Choi and Cho explain that eventually, the lenses could be repaired at home as well—through UV light from devices used to cure nail polish, or indoor grow lamps for houseplants.

Atop the hydrogel structure, an additional layer of polymer was applied that resists bacterial buildup and abrasion, even after repeated contact with sandpaper. It retained moisture better than commercially-available contact lenses too, and the repaired scratches had a mere 2% perceptibility score, suggesting that multiple scratches could be repaired and tolerated before a replacement was needed due to transparency issues.

Additional testing for South Korean regulatory approval is needed, the authors explain, before the product can undergo market testing. The technology could reduce waste and lower replacement costs for millions of contact lens users.

The study, funded in part by the National Research Foundation of RoK, was published in ACS Applied Polymer Materials.