Wide-Brim Hats Don’t Interfere With Photochromic Sunglasses

On the tail-end of a recent eye exam I had a chance to ask the doc one of my longest-burning questions: do wide-brim hats interfere with the ability of photochromic lenses to darken in response to UV light?

Her answer was no.

For context, almost all photochromic lenses rely on ambient UV light in order to trigger the darkening effect. However, car windshields block the portion of the UV spectrum that the lenses are sensitive to, effectively reducing them to regular fixed-transmission sunglasses while driving. Since wide-brim hats block all of the direct sunlight that would otherwise hit the lenses, I wondered if they might introduce a similar canceling effect in the outdoors. Fortunately, my concerns were unfounded: apparently there is sufficient ambient light to keep them functioning as intended.

For the curious, DriveWear lenses also include photochromic particles which are sensitive to visible light, making them effective while driving during the day (I have a pair, they’re great). Upping the ante, Zeiss DriveSafe lenses are available in a transition (photochromic) variety and can also be used at night. Craziness.