# Anyone use photochromic eyeglasses?

**URL:** <https://boards.straightdope.com/t/anyone-use-photochromic-eyeglasses/537824>\
**Category:** In My Humble Opinion\
**Created:** [April 30, 2010, 2:46am UTC](https://boards.straightdope.com/t/anyone-use-photochromic-eyeglasses/537824 "2010-04-30T02:46:28Z")\
**Posts on this page:** 3\
**Page:** 2

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**Author:** ![pudytat72](https://avatars.discourse-cdn.com/v4/letter/p/ce7236/32.png) [@pudytat72](https://boards.straightdope.com/u/pudytat72)\
**Post date:** [May 5, 2010, 3:52am UTC](https://boards.straightdope.com/t/anyone-use-photochromic-eyeglasses/537824/21 "2010-05-05T03:52:39Z")

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I have the Transitions lenses and I keep a pair of clip-on sunglasses in the storage bin just above the rear-view mirror in my car. Easy habit now to use them in the car and keep them there.

The lenses getting dark are a disadvantage when you are having your picture taken outside, and sometimes I have trouble seeing the screen of my camera when I am taking pictures in sunlight.

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**Author:** ![GaryM](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garym/32/241_2.png) [@GaryM](https://boards.straightdope.com/u/GaryM)\
**Post date:** [May 6, 2010, 2:47pm UTC](https://boards.straightdope.com/t/anyone-use-photochromic-eyeglasses/537824/22 "2010-05-06T14:47:07Z")

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I also have had the [Transitions](http://en-us.transitions.com/en/experience/Pages/default.aspx) lenses for years and just recently, after cataract surgery, got a new set. They darken much faster than the older ones did.

True, they don’t darken much, if at all, in the car, but they now have what are called [Drivewear Lenses](http://www.drivewearlens.com/effect.php). You may find these more suitable.

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**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\
**Post date:** [May 6, 2010, 3:34pm UTC](https://boards.straightdope.com/t/anyone-use-photochromic-eyeglasses/537824/23 "2010-05-06T15:34:01Z")

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There have been photochromic glasses going back decades, both in glass and in plastic lenses. I’ve actually made photochromic plastic items at one of my jobs (which made plastic visors and lenses).

Photochromic materials invariably change more rapidly with shorter wavelengths, so they’re going to darken more rapidly (and usually darker) under direct sunlight than through glass – that’s pretty much a fact of light. There are photochromic dopants that work better under longer wavelength than others (which is what I worked on), and presumably these are what is in the driving glasses **GaryM** mentions. But even those will work better out of doors.  
Another sad fact of life is that the darkening tends to get worse with age. Invariably the active centers begin to change through the years, changing to states where they can no longer transition from dark to light mode. You can minimize this and delay the onset through use of additives, but I feel pretty sure that even Transitions lenses do this.

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