Crazed lenses: I just opened the case and they looked like this!

[AngeHamm]

You know what I'm talking about, the patient whose lenses are crazed from edge to edge and swears they just put them on today and they looked like this. "Were they exposed to any heat, left in your car for example?" "No, I never leave my glasses in my car!" "Was there some stress or pressure applied to the lenses?" "No, I'm very careful with my lenses!" So you smile and nod and order new lenses under scratch warranty, knowing in your heart of hearts that this patient probably left their glasses in their car all day and just didn't want to admit it.

Not so fast.

Over the past two months, I have had FOUR sets of lenses come up crazed. I'm talking about my lenses, for my personal glasses. Three crazed in the centers, one crazed from edge to edge. I never, ever leave them in my car, and I clean them with professional products, usually at work. Four. Different. Pairs. Two different manufacturers, two different materials, three different AR coatings, two stock, one surfaced. No rhyme or reason to it. What gives???

Oh, and naturally all four are out of warranty.

[Flux3r]

My guess would be they are cut too big....

[Wes]

It's getting cold out. And its probably warm inside. If you're outside long enough to get them chilly, and then come into a 75° room, that might be enough to do it. We tend to think heat, but it's actually rapid temperature change that does it.
Do you have any new hobbies?

[AngeHamm]

No, no, and no.

[mervinek]

Wow... 4 pairs? Different materials and different manufacturers? All edged at same lab? Maybe too big?

[AngeHamm]

All edged by me. Trust me; they're not too big. And even if they were too big, a couple were edged 4 years ago.

[mervinek]

Crazed in centers? I've had that happen when chuck pressure too high. But that usually shows up within a day or two... never a few years later. Odd.. Are the lenses too thin? I still would think craze would show up sooner and not after years.

[AngeHamm]

Crazed in centers? I've had that happen when chuck pressure too high. But that usually shows up within a day or two... never a few years later. Odd.. Are the lenses too thin? I still would think craze would show up sooner and not after years.

My very thought. One of the pairs is 4 years old, one 5; both 1.67 Trans Grey with Avance. The most recent one is 1.67 Zeiss Photofusion with PureCoat; I put them in the ultrasonic and then couldn't seem to get the streaks off them when I cleaned them afterward. Turns out the "streaks" were edge-to-edge ripples in the AR coating. WTF??? I've put lenses in the ultrasonic thousands of times with no ill effects. Whatever crazed those lenses has to have been something else. The fourth pair is 1.74 with Crizal Sapphire. It's madness; there's no pattern and no logic.

[mervinek]

What was in the ultrasonic? I've had office staff sneak in jewelry cleaner in mine without me knowing it. It was ugly. Just a thought.

[CME4SPECS]

Really? 4 and 5 years old? Well...time to get those eyes examined and spring for some new ones!

[AngeHamm]

Nothing in the ultrasonic but water and a couple squirts of dish soap.

[mervinek]

new dish soap? Antibacterial stuff can craze.

[Tallboy]

Are they all long B measurements with an front Aspheric design? Are they all minus lenses?.

EDIT: Though this is by far the most common culprit, it would rear its ugly head WELL before 4-5 years...

[Uncle Fester]

There's a reason why you cannot get a warranty beyond 2 years.

[Chris Ryser]

It's getting cold out. And its probably warm inside. If you're outside long enough to get them chilly, and then come into a 75° room, that might be enough to do it. We tend to think heat, but it's actually rapid temperature change that does it.

Wes is right all the way.

You will see more of it, as fall progresses into winter.

If lenses are CR 39, they can be easily stripped of the AR coating in 5-10 seconds, and re-coated, or tinted, or just used as a spare.

AR stripping has progressed dramatically over the last 2 years in optical wholesale labs, but not by optical retailers, and they are missing out in an important service area.

[Jim Schafer]

have not been on for awhile and this thread caught my eye......

working with new lens materials in the 90's we found lenses (hardcoated and ar treated) that were cleaned in our ultrasonic cleaning lines, tended to craze or crack over hand cleaned. we analyzed and found that the us cleaning caused micro cracks, that later opened to where they were visible.

These were lenses that were in solar or quv testing,...and what caught my attention was that the crazing only happened when a certain tech followed a group through the testing...instead of hand cleaning, he would use a cleaning line for one of our production lines while he took a break!

I remember sharing the info with AR and hardcoating experts and they had experienced the similar results...

[Happylady]

I never put AR lenses in an ultrasonic. I have always understood it was bad for AR lenses.

[Wes]

have not been on for awhile and this thread caught my eye......

working with new lens materials in the 90's we found lenses (hardcoated and ar treated) that were cleaned in our ultrasonic cleaning lines, tended to craze or crack over hand cleaned. we analyzed and found that the us cleaning caused micro cracks, that later opened to where they were visible.

These were lenses that were in solar or quv testing,...and what caught my attention was that the crazing only happened when a certain tech followed a group through the testing...instead of hand cleaning, he would use a cleaning line for one of our production lines while he took a break!

I remember sharing the info with AR and hardcoating experts and they had experienced the similar results...

Yay, I learned something today! Thanks, Jim!

[Wes]

I never put AR lenses in an ultrasonic. I have always understood it was bad for AR lenses.

Anyone have a scientific theory as to why?

[Boldt]

I think Jim is on to it. The sound waves cause any micro cracks to enlarge to where we can see them. It could also depend on the quality of the AR used. I've had fresh edged basic AR craze when a trainee put some frames in a sonic cleaner.
I'd say age, how well the lenses are treated, and how intense the waves are. Knowing that sound can cause structural damage at certain frequencies, and water magnifies it I'd say it's a combination of factors. I usually remove lenses before I sonic the frames.

[Wes]

Perhaps like singers can shatter crystal if they hit the right pitch and apply enough energy?

[AngeHamm]

Thanks, friends! Ultrasonic may explain one of these issues, and I'll avoid it in the future. (Though it has no connection with the other three, neither does temperature.)

[ml43]

Perhaps like singers can shatter crystal if they hit the right pitch and apply enough energy?

resonant frequencies amplify each other, perhaps?

Talking about two ends of the range though, in this case we are dealing with a very low frequency.

Maybe more similar to the way they use concentrated sound waves to break up rocks/stones or kidney stones?

[Boldt]

Right on, lower frequencies do more damage than higher and they travel better in liquids.

It could be as simple as the cold snap + sonic cleaner + age = crazing.

[AngeHamm]

One thing is for sure: When a patient comes in with crazed lenses and no idea how it happened, I will give them a lot more benefit of the doubt than I have in the past.