I have worn Ray-Ban's for years that I got from Sierra Trading Post. Great glasses,but they finally broke.
I am wearing a pair I found in a mountain stream . I looked them up and they cost $6.50.
I've looked at Ray-Bans and Maui Jim's and you can hardly find any less than $100.
So what is the real difference between a $100 pair and a $6.50 pair? Are we talking Tilley's vs Boonies?Is there a real optical difference?
yes
there is a difference between a pair that is $100 and a pair for $6.50.
There is less difference between a pair that is $50-60 and a pair that is $100. The main difference there is the name brand. You can get some very nice glasses for around $50 if you look around.
What is the difference?
It’s all about the coatings.
The coatings are metal so thin you can see through it. You want a polycarbonate base that blocks 80% of all light. It should be polorized. It should say Blocks 100% UVA and 100% UVB. If it does not say it, it does not have it.
lens quality
Not all inexpensive glasses are bad, but some are.
I’ve noticed that some – brand new – make things slightly hazy as well as darker. It makes objects seem more distant, and you end up straining to see clearly. Distortion at the edges of the lens is another common problem.
But I’ve seen some tinted safety glasses for under $10 that I thought were pretty good, and some glasses for more money that were junk.
To add to Angstrom’s post
It would be a good idea to look at industrial safety glasses too. Many are made by big-name optical mfgrs, and have very good lens quality. They have progressed far from the 50s dorkey “safety” look too. And many are available with “cheater” reading lenses as well - these are popular with my employees. We are all getting older.
Sure, the Ray-Bans and Oakleys are of superior clarity - but maybe good quality is all we really need. An easy test is to hold a set of glasses about a foor from your eyes and look at fluorescent bulbs: Look for parallel distorsion in the lenses.
Jim
Wallmart, fishing section
For about $15 I got a pair of what seem to be really nice glasses. Polarized, block all sorts of UV, wrap-around, do not distort at all. For another $1 I got the neoprene band that matches them and also makes them float (nice feature, that saved them for me last time - I came back to the spot where I lost them o nthe water and saw them floating, waiting for me to pick-up)
Ditto on Walmart…
I just got a pair of polarized clip ons that look like the ones my eye doctor sells for $100,and they cost $9. They match my glasses shape better too. Just match your frame to the chart,and pick the part # off the display. Don’t notice any distortion. If I break or loose them it takes a lot of $9 to make $100.
billinpa/md & apple
The Laws of Nature (and sunglasses)
I’ve done a lot of research over the years… and I can tell you that there is one rock-solid ‘law of nature’ that applies to sunglasses. The more money you spend on a pair of sunglasses, the sooner they will meet their demise.
My quick calculations indicate that a $6.50 of sunglasses should last about 100 years.
You said it …
Polarized – UVA – Walmart $10 - then I don’t cry when I loose them, but agree can’t seem to loose a $10 pair, but pay $100 and can’t ever seem to find them …
… or better yet - sit on them 
My husband has a cool pair from Walmart that has little magnified circles in the bottom middle. This allows him to read maps and such when we are paddling. He loves these.
difference for me
is that i want good optical clarity at a full range of vision (cheap lenses often distort near the edges), polarized lenses (not all polarized lenses are equal, if you compare cheap polarized lenses side-by-side with expensive, you can see the difference), and durability (big one for me as i use them for lots of jarring, impact type sports.
Both
I have several pairs of Raybans. I have prescription lens in a couple of them.
But after losing a couple pairs of Rayban, I only wear Walmart sunglasses in the kayak.
Consumer Reports notes that…
the only differences are sometimes the quality of the frame (eg metal versus plastic), and if polarized lenses, better, and if coted lenses, the integrated coating rather than spray on topical coatings are better, but otherwise, if you get 100% UV protection, same.
So, basically, same.
I like Oakley Monster Dogs and Monster Pups, though, for $75 glasses that are great. Check eBay. See ya.
I wore Ray Bans for years
The last pair I had fell into the Atlantic ocean when I rented a Cessna 172 and took some friends flying. I probably shouldn’t have been flying with the windows propped open if I really cared about the glasses.
From that point on, I have worn tinted safety glasses on a daily basis. I have not been able to tell any difference except the price.
I just drop into an industrial supply house and pay a few buck. I couldn’t care less if I destroy or loose them now.
Peace of mind is worth a lot.
Ditto again on Wal-Mart they also have
magnifing ones now. Like bifocal reading glasses.
$93.50… that was easy
Hunting dept, tooo
I wore shooter’s glasses for years. Remington makes some inexpensive wraparounds that are advertised as distortion-free. No biggie if I lost them (Which happened about once a year).
I stopped wearing contact lenses about a year ago, and began wearing prescription Sea Secs, so that I could see what I was doing. They were about $240 for prescription lenses. I wear them cycling and skiing, too, so they were worth the $$$$.
GK, you can cipher!!!???
Wonders never cease.
Optometrist
I wear prescription sunglasses and so does my wife, Optically clear Plano (Plain glass) lens, polarized, hardened, scratch resistant with titanium frames.
What you do is go to the eye doctor, tell them the sun hurts your eyes and you are worried about uv rays. Explain to them why you want them (sun and eye protection in the outdoors), pick your frames and let your insurance pay for them.
Mine cost $12, my wife’s cost $19 after insurance and we replace them every two years 
That’s dandy…
if you are lucky enough to have vision coverage,but a lot of people don’t.
billinpa/md & apple