Transition lenses

[shadowcat]

I have transition lenses on my glasses & I really do like them. They do come in quite handy when out in the sun & I don't have to carry clips or prescription sunglasses. However, today I had a real problem with them and I'm curious if anyone else has had this or knows why it happens. It was very sunny today (Sunday) and they turned quite dark, which was great, during the day. However, they never turned back to clear. When we started to head back down off Gothics it was around 6:30 and they were so dark that even with my headlamp on it really hampered my vision. In the summer I don't recall ever having this issue & I'm thinking maybe it has something to do with the snow (the whiteness or the light reflecting off it) or the cold; or both. I do have regular glasses I can wear next time but I got these specifically for use hiking and biking and if this is something I can fix or if the lenses are faulty I'd like to know. Any ideas???

 

[David Metsky]

I've never had this happen with my Transition lenses, and I've been out in the bright snow many times. I'd check with your eye doctor; have they turned back to clear now?

 

[Chip]

"Because photochromic compounds fade back to their clear state by a thermal process, the higher the temperature, the less dark photochromic lenses will be. This thermal effect is called "temperature dependency" and prevents these devices from achieving true sunglass darkness in very hot weather. Conversely, photochromic lenses will get very dark in cold weather conditions, which makes them more suitable for snow skiers than beachgoers while outside. Once inside, away from the triggering UV light, the cold lenses take longer to regain their clear color than warm lenses."

When Jay H and I did Katahdin there was a guy in our group that had prescription glacier glasses, not transitional, just VERY dark. He was blind without glasses but only brought these. It was overcast all day and got less bright as the day progressed. The guy was basically blind with these dark glasses on. I guess the lesson is: If you need glasses, bring spares.

 

[Kevin Rooney]

In my experience, transition lenses also turn dark when it's cold, despite what the optical shop will tell you. As you found out, this can be a real problem in late afternoon/early evening. Have had at least 5 or 6 pairs over the years which have done this. The only real solution for winter hiking in cold weather is to have two pairs of glasses - one regular (non-transition) and regular prescription sunglasses.

I usually buy my glasses thru Costco. Have no idea which lab actually does the work.

 

[shadowcat]

transition problem prob the cold

yes i am pretty sure the cold and the snow is what screwed up my lenses so another lesson learned - bring a spare. but that's a good lesson for anyone who relies on glasses. if mine ever broke it would be nightmare trying to hike w/o any glasses on. i am so badly nearsighted i'd be a total stumbling fool w/o them!

 

[Kevin Rooney]

As another wearer for whom eyeglasses is not optional - this might or might not apply, but just in case -

I learned several years that the size of the eyeglasses (I prefer wire rims) is important. At the time, the fashion was to wear larger rims than are common today, and I found on more than one occasion I'd be cranking uphill, very warm with a bit of sweat on my face, even on cold windy days. This is particularly true when hiking Lincoln/Lafayette via Little Haystack, when the steep ascent is protected by trees until near the summit. In that direction, the wind is nearly always a headwind from the NW. What I found out - the hard way - is that my larger wire-rimmed glasses would slip down my nose, touching each side of my nostrils, and the cold would be tranmitted to my skin, creating two bits of frostbite when the frames touched the skin as I now hiked north towards Lincoln. This wouldn't be noticeable to me until about Tuesday when my co-workers would comment on the two brown patches on either side of my nose, which by now had also blistered. Even after I was aware of this possibility I found I couldn't avoid it entirely, since it was so localized, as flash-freezing like this isn't noticeable at the time as it's painless. The only way I could solve the problem was to get smaller glasses, which I did, and I did not get transition lenses.

Problem solved, but it took several instances of minor frostbite to convince me that efforts to pay better attention simply wouldn't work.

I saw a related instance (I think I've posted this before) of a fellow hiker with whom I did Monroe under very adverse conditions - cold, windy, subzero, etc. He was using a neoprene facemask, and had cut tiny holes near the ears so the eyeglass frames could pass though. On this day, even with goggles, these holes - maybe 1/8" in diameter - had allowed enough cold air in to frostbite a small area on each temple. He wasn't aware of it until we noticed it over pizza at the Mooseland Grill (now burned down) that night. It took several minutes to sort out the details, as he was certain he'd had no exposed flesh whatsoever, but these tiny holes had been enough to cause damage.

 

[woodstrider]

Transitions lenses

This is a common "problem" when using photosensitive lense materials especially in the cold, but easily remedied.

Just put your eyeglasses in a warm place- say an inner pocket- for a short time until the lenses lighten up again. The material is temp. sensitive- the cold inhibiting the shrinking of the ... blah blab blab...

I used to work in this field.

 

[Kevin Rooney]

This is a common "problem" when using photosensitive lense materials especially in the cold, but easily remedied.

Just put your eyeglasses in a warm place- say an inner pocket- for a short time until the lenses lighten up again. The material is temp. sensitive- the cold inhibiting the shrinking of the ... blah blab blab...

I used to work in this field.

OK ... and a few minutes after you remove them from an inner pocket, put them on, they turn dark again if it's cold. They also clear when you make it to your vehicle with the heater on...

How is putting them in your pocket a solution?

What am I missing?

 

[woodstrider]

Transitions lenses

OK ... and a few minutes after you remove them from an inner pocket, put them on, they turn dark again if it's cold. They also clear when you make it to your vehicle with the heater on...

How is putting them in your pocket a solution?

What am I missing?

The original problem was once the sun goes down- how to get the dark lenses to turn from the dark phase back to light phase, right? Putting them in an inner pocket, where is is warm, will facilitate the change from dark to light phase.

Try it out.

 

[Kevin Rooney]

The original problem was once the sun goes down- how to get the dark lenses to turn from the dark phase back to light phase, right? Putting them in an inner pocket, where is is warm, will facilitate the change from dark to light phase.

Try it out.

So are you saying that - after there's no longer intense UV light, only cold temps - if the glasses are brought to body temp or thereabouts, they will not turn dark again once they're re-exposed to cold temps?