First-Ever Photochromic Contact Lenses May Replace Sunglasses

I wear glasses, but don’t own contact lenses. And while this normally doesn’t make a difference, staring into the midday sun often leads me to think about switching to contacts simply so I can wear sunglasses.

Well, just as I all but convinced myself to switch, the Institute for Bioengineering and Nanotechnology (IBN) in Singapore goes ahead and makes sunglasses all but useless for contact lens wearers. Behold, the first ever photochromic contacts.

Photochromic lenses, glasses that darken in bright light, have been around for decades. They consist of lenses coated in photochromic dyes that change shape when irradiated by sunlight. When the dye changes, they block out the sun, darkening the lens.

Unfortunately, the small size and malleable material of contact lenses make them impossible to coat uniformly. Therein lies the breakthrough. Rather than coating the lenses in dye, the IBN team embedded the dye within the contact lenses. The resultant lenses not only darken in the light, protecting the wearer from UV rays, but do so orders of magnitude faster than regular p glasses.

The increased speed results from the material used to make the contact lenses. The IBN researchers had to develop a unique, spongy material that securely contained the dye, but remained flexible like a regular contact lens. Luckily, the spongy material also gives the dye more room to change shape, allowing the dye to photochromic from transparent to opaque faster than when used as coating.

But while this invention’s certainly neat, I’m still going the sunglasses route. It may not be as convenient, but it looks much, much cooler.

[via Technology Review]