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What Are Photochromic Lenses? Photochromic Lenses Comparison

You’ve likely heard of Transitions lenses, but did you know that just like Kleenex are a brand name of tissues, Transitions are a brand name of a type of lenses called “photochromics”? In today’s blog, we'll be comparing the types of Photochromic lenses on the market in an attempt to answer your question - are Transitions brand photochromics really the best? The theme of the eye school blog is lifelong eye-ducation so I always invite you to let me know what you’re learning and feel free to leave comments with questions or suggestions about new topics! Alright eye school pupils, let’s take a look at today’s topic: Photochromic Lenses!

What are photochromic lenses?

They are designed to be clear or mostly clear while indoors and automatically darken when exposed to UV light, allowing for better visibility in the absence or presence of light. Their biggest PRO is they are regular Glasses that turn into sunglasses! 2 in one, yay! Their biggest CON is they don’t always turn dark or turn back from dark to clear as quickly as you’d like them to. So then they're stuck at their desk after lunch waiting for their glasses to turn when they just want to get back to work.

How do photochromics work? They are made with trace amounts of silver chloride, when exposed to UV the silver molecules gain an electron from the chloride to become silver metal. This gives the lens the ability to absorb visible light, turning darker. It’s a chemical reaction in your lenses, over and over! Then, copper chloride strips silver of its chloride electron, helping the lenses return to their original non-absorbing state.

What different types of photochromic lenses are out there?

  1. “Regular”

  2. Regular Polarized

  3. Darker than regular

  4. Darker than regular polarized

  5. Sun lenses

  6. Acuvue Oasys Transitions Contact Lenses

As a general class we can talk about what people usually call "regular transitions" or "regular photochromics", there's also regular that come polarized and then there's a darker version that's regular photochromic but in the case of transitions they are called extra active.

You can also have a darker lens that comes polarized and then there's different types of sun lenses for instance the transitions drivewear i've made a video about. Those already are sort of a greenish color that turns more copper with sun exposure but there are many other brands that have photochromic sun lenses. In fact one of our sunglasses brands Zeal which we've done a video about, has a number of sunglasses that come already tinted and then they get even darker when you're outdoors.

What brands carry the lenses?

  1. Transitions Brand! Gen 8, Vantage, Xtractive, Xtractive Polarized, Drivewear, Acuvue Oasys Transitions!

  2. Zeiss Photofusion (many Colors Available) NEW Extragrey Available? 15-30 s to dark, 3-8 min to light.

  3. IOT Neochromes (House brand) 3 minute fade back advertised on website. “Quickly adapts” Blocks 100% UVA/B

  4. VSP, Hoya, etc!

In terms of brands we have the biggie, which is transitions brand. This is the one everyone's heard of; their regular version is now called "generation 8" and they also have "vantage" which are their regular transitions® lenses that polarize as it changes color, and they have extra active lenses which get darker behind a car windshield and are darker in general.

Then we have xtractive polarized which is brand new to the market and finally driveware which is their sun lens. That's especially meant for driving and goes from a greenish to copper tint. Also within the transitions umbrella we do have Acuvue Oasys transitions. They're actually contact lenses you can wear that have transitioning capability. I did make a video on these contacts as an option.

The second type of brand that carries this photochromic lens is Zeiss. They have something called the photofusion. They have many, many colors available in their photochromic lens and they even have an extra gray available now that they claim takes 15 to 30 seconds to darken and between three and eight minutes to get light again. We actually tested this claim in the video attached in this blog.

Our next brand of photochromics are called Neochromes, these are made by I.O.T. and they are what we commonly would consider a house brand. In my practice this is our private label, also called our independent pay lab. IOT has a number of different progressives and they have their own version of photochromics that are called Neochrome. We call this our house brand. On their website they advertise a three minute fade back. That's for going from dark to totally clear and in terms of getting dark they just say that it "quickly adapts". They also claim a hundred percent UVA & UVB protection in their lenses.

These three brands we've just talked about: the Zeiss photo fusion, the iot neochrome and the transitions were actually tested by me in the attached video and we find out how quickly they turn dark, how much UV they are protecting against and then how long does it take them to get clear once we are inside again. but i would be remiss without mentioning that there are indeed more photochromics on the market than i took the time to purchase and show you in the video and discuss in this blog.

Our vision care plan, called VSP, has their own sort of house brand of photochromics. there's a lens company called Hoya that has photochromics as well and i'm sure there are many many more on the market so this is just a small representative sample of a house brand, one brand named Zeiss and of course the most well known market brand, transitions lenses all compared to each other.

We put these lenses to the real world test

Indoor Comparison!

  1. Method: We will change all 3 with a UV lamp very quickly. Test on our UV meter.

  2. Does it block UV A/B?

  3. How long will it take to get dark?

  4. How long does it take to get light?

The first test I did was an indoor test comparison. the method we used was applied to all three brands using my UV lamp, that i purchased for this video specifically and we will be able to change them very, very quickly and then we tested on my practice's UV meter to just confirm that all of these glasses do indeed A. get dark and B. protect against UV.

So do these lenses block UVA and UVB? We put each one under the meter and recorded yes or no if it blocks against UVA and UVB at the level of uUV 400. In the video above you can see that every single one of these brands actually did block against uv a and b. they all measured uv 400 on my uv measuring device. Our next test was how long each of these takes to get dark. What i did was to take them all outside, we kept them covered up into towels, when they're all clear and we showed you in the video that they turn. We also put a timer on the screen to show you how quickly they're turning in comparison to each other.

Together we watched all of the lenses change. I'm happy to say that they all indeed did get dark within 30 seconds! There were a couple of little things I noticed; number one the transitions xtractive (not the xtractive polarized) didn't get as dark as fast as i thought it would. secondly the neochromes, i was very impressed with how dark those got. In fact, I thought they got just about as dark as the extra active lenses did so that was just something to note. zeiss performed just as I thought it would, transitions gen 8 performed just as I thought it would and I thought really among all of these lenses they all appeared about as dark as each other, once they were fully turned. On this test they all get a big green check mark because they all made it within 30 seconds!!

Outdoor Demonstration

  1. Can we see them turning back to clear inside the office?

  2. How long does each brand take to turn back to clear?

Our next test was to bring all of those glasses back inside and we watched to see how quickly they can turn back to clear. We'll stop the clock at three minutes, five minutes and eight minutes, to check in and see which ones have changed and which ones still have a ways to go. We want to report to you as accurately as possible how long these lenses take to go from dark to light.

We took an opportunity to watch all of these lenses next to each other changing back to clear and one thing I do want you to know is that we were filming the video which inspired this blog in the middle of April in the south. so i'm located in North Carolina; that's where my office is.

I also want to orient you a little bit in this optical where I'm filming. There is a big window next to me and there is no UV protection in that window and so there is some inherent UV light coming into our filming space as we were watching these glasses. However, I think that this makes our test a little more real world, right?!

As you think about when you're going to wear your photochromic lenses, you most likely are going to be in environments where there is a little bit of UV. Just know that and take this particular comparison with a grain of salt and these are the judgment calls that I made as the photochromics changed back.

Which one is best?

I'll offer a kind of summary; I was really, really, really impressed with the neochromes. I actually thought that those changed the fastest. We used the gray neochromes, they also come in brown, just so you know but that was really impressive to me. I thought they changed back the absolute fastest!

I was also interested to see that in our transitions gen8 there was a small difference between the gray and the gen8 colors. The gray definitely turned back faster. This particular gen8 color is sapphire; so just you know we can't speak for any other gen8 color but that was a direct comparison and in this case; the gray turned back faster than sapphire!

Not surprisingly our xtractives took a little bit longer to turn back and unfortunately even at eight minutes, were not turned back. The Transitions regular xtractive had changed back but our xtractive polarized; the brand new lenses that just came out, even at eight minutes in this test, were not changed back to their clear state.

Finally unfortunately, the Zeiss photofusion did not perform as well as I wanted it to or hoped it would. I thought it would be comparable to our gen8’s or our Neochromes but actually at eight minutes, it wasn't even turned so that was pretty surprising to me.

That’s it for today’s lesson! I hope you enjoyed it and learned something. Remember, learning is lifelong!



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