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glass lenses = bad?(6 posts)

glass lenses = bad?gtx
May 31, 2002 9:04 AM
After trying Rudy Projects and a few other cycling/sport type sunglasses I've decided to just get another set of Ray Bans (I like their gray lenses the best). So the question is, am I stupid to even consider glass lenses for an activity like cycling? Are the "polycarbonate" lenses considered much safer? Thanks!
you betMel Erickson
May 31, 2002 9:11 AM
Shatter resistant lenses are a must and glass doesn't do the job. I don't even think you can get shatter resistant glass lenses anymore and if you can I would think they'd cost a bunch. Besides, polycarbonate and other types of plastic lenses are a lot lighter, which makes for more comfortable glasses, especially when you sweat. The only reason I can think of for getting glass lenses would be scratch resistance but modern coatings on plastic lenses are pretty effective.
re: glass lenses = bad?DINOSAUR
May 31, 2002 9:29 AM
I couldn't see forking over a lot of money just for eye protection when I rode. I purchased a pair of house brand Nashbar "Adonis" sunglasses that came with 4 replacement lenses on sale for $29.00. They fit better than my old Smiths as you can adjust the temple length. For safety reasons, I'd avoid glass. When I crashed two years ago I was wearing my Smiths and they survived intact, even though I received a nasty black eye. I think glass ones would have shattered.
thanks guys--I'm convinced nmgtx
May 31, 2002 2:14 PM
re: glass lenses = bad?HAL9010
May 31, 2002 2:18 PM
True optical glass lenses are tempered and shatter resistant. US law requires that all (not a small sample of but all) glass prescription lenses be tested before delivery to the consumer they were made for. The test is very harsh. The same test if performed on plastic will leave a damage mark on the lens. This will not matter to you if you don't require prescription lenses as I do.

On scratch resistance, plastic lenses, coated or not will still scratch far faster than glass. Glass lenses will not scratch if handled with reasonable care and quite often with poor care. Plastic lenses will develop scratches (even coated) even with seemingly good care.

On shatter resistance; if you are hit in the eye by something that results in breaking the lens you will probably have other trauma that would be far worse to worry about than just the broken lens material. Yes the plastic is flexible but the tensile strength of optical glass is very high. Glass is heavier than plastic but some of us are not bothered by the weight. But again this probably matters little to you if you don't need prescription lenses.

Several of the sport glasses brands offer prescription insert options. I have been be-specticaled for about 35 years and active in cycling and other sports with no mishaps to my specs. Hey I gotta weare them all the time any way so I have incentive to take care of them.

Spend some serious coin on your polycarbonate lenses to give yourself the care incentive too or consider some of the wrap-around glass Ray-Bans or Vuarnet's (Both serious coin). If you are worried about them falling off put a strap on them or get them adjusted correctly.

To summarise: nothing less safe with true optical glass lenses. But you owe it to yourself to wear some sort of eye protection instead of none.

I do get carried away...
great postgtx
May 31, 2002 4:48 PM
I've been riding with the standard Ray Ban wrap arounds with glass lenses for 10 years with no problems--this includes mtb riding. The glass lenses hold up very well, and I know plastic won't, which is the reason for my original question. I assume these are what you call optical glass--they're $100 sunglasses. They are great lenses. Hmmmmm.