Polycarbonate vs. Trivex: what do you know??

[opticalmomx2]

I'm a student learning about optometry and I am writting a paper on the topic of polycarbonate vs. trivex lens'.
Which one is better? Why is there a debate? Why choose one over the other?
Anyone who can help would be appreciated!

[DragonLensmanWV]

Hint: the Search function is your friend. There are multiple threads about this.

[NJEyeGuy]

Oh Man! What a loaded question... This topic has been pretty much killed though so a good search isn't a bad idea. I will tell you that from the trends in legal proceedings the backing for safety is definitely in poly's favor.

[edKENdance]

Oh Man! What a loaded question... This topic has been pretty much killed though so a good search isn't a bad idea. I will tell you that from the trends in legal proceedings the backing for safety is definitely in poly's favor.

Do tell

[shanbaum]

I can't find any record of any published decisions related to litigation involving lenses made of Trivex in any state or federal court.

Of the few cases I can find involving lenses and poly (based on a cursory search), one from 1986 involved a duty to warn when providing glass instead of poly for safety glasses (the court found that there was no such duty); another involved alleged negligence when an OD provided glass lenses to a child who claimed to have requested poly. I don't see any that involved claims of inadequate safety of poly, and as I mentioned, none at all involving Trivex.

I don't have time to do an exhaustive search, but there appear to be surprisingly few cases on this subject matter in recent years. I'm not using the search tool I usually use, so my results may not be reliable. I'll try to look into this further when I have some time.

[chip anderson]

I suspect that most "safety regualtions" have more to do with the EPA, OSHA, DOT and other agencies getting a chance to exert power and pretend like they are qualified to save us poor people unable to look out for ourselves.
Hell our legislature passed a law outlawing nitrous oxide used as a power supliment after one hiway patrolman lost control of his car trying to keep up with someone running it. Everybody got a great deal of patting on the back for the momentous accomplishment.

Chip

Note: key word here: most not all

[NJEyeGuy]

No I guess you are right there is no legal precedent for Poly or Trivex being unsafe, however, since legal precedent already states that polycarb is the standard I'm not willing to be on the stand to argue the merits of Trivex no matter how good they are(and I do love Trivex for numerous applications). It's like in medicine, if the doctor gets sued and they have done anything not considered "standard of care" they are at fault... even if it's in good faith.

[Nikolay Angelov]

When you consider safety:
In many situation clear vision will be the most important safety factor.

I don't know how wise it is to reduce vision quality, for the sake of increased impact resistance.

If you blindly follow that line of reasoning you will end up with a opaque block of steel for lenses.
When operating machines in an industrial dusty environment even glass may be the safest option, as it will scratch the least and thus give operators better vision.

On the original topic, polycarbonate is much cheaper and faster to produce so manufacturers love it.
To put things in perspective, the everyday Compact Disc/DVD/BluRay Disc etc goes through roughly the same production process as a lens.

For reference, here is a video showing how a CD is made:


Which is "better" depends on the qualities you value (optical characteristics, mechanical characteristics, manufacturing costs, manufacturing time etc.).

Best regards,
Nikolay Angelov