Sunglasses

[Matthew]

That may have been true once, but not any more with the high-tech lenses I have, which are formed to meet the following prescription:

-9.25/-1.00x125/+2.50
-3.50/-2.25x050/+2.00

Essentially, these lenses are individually custom-designed. I understand they use mold shaped by computer-controlled machinery to form them, and it takes a lot of math to write the code for each prescription.

I know they are machined. My doc said he'd need to write a particular prescription for contacts that would be different from my glasses. That's been a while, maybe things are different. That got me thinking that there's really a difference somewhere.

But what I meant by 'even' numbers didn't come out quite right. As in your prescription, all numbers are in factors of .25, .5, 125, 50. Mine has numbers like -1.62, x009, x016. I don't know if that's something that contacts can be made in, or if they'd have to be rounded off to -1.60, x010, x015.

But I see that our readers are the same!

 

[sba55]

sba, those are the sunglasses of which I speak, still a bad idea?

I'm not an expert, but based on what I know - yes. It's very unlikely that those sunglasses truly have effective UVA/B protection, and they generally don't protect at all against the equally bad UVC...

 

[sba55]

Well, the label says they're UV-A/B blocking, so I guess I'll have to ask my optometrist. Of course, she sells the same ones on her "bargain" stand (albeit for more money than WalMart), and I don't think she'd sell junk.

I think that's a good idea. I'd ask him and see what he says.

I have asked mine and he has made it very clear in the past that he thinks spending a little more than $5 is a very good idea if your eyes are important to you.

 

[Trapper John]

I'm not an expert, but based on what I know - yes. It's very unlikely that those sunglasses truly have effective UVA/B protection, and they generally don't protect at all against the equally bad UVC...

It would be useful to be concerned about UV-C if that range of wavelengths occurred in any appreciable amount in nature and our exposure was enough to be hazardous.

The only practical way to get UV-C exposure is to pull the light source out of a cooling tower, pond or water treatment plant where artificial UV-C sources are in use as sterilizers and to be dumb enough to stare at it. The sun just doesn't shoot enough UV-C at us to worry about.

UV-A and UV-B attenuation is pretty much a slam dunk from a physics and engineering perspective. If you like your designer sunglasses, that's great, but you don't have to pay designer prices to get UV-A and UV-B protection, or protection from nonhazardous naturally-occuring UV-C light either.

 

[Trapper John]

That may have been true once, but not any more with the high-tech lenses I have, which are formed to meet the following prescription:

-9.25/-1.00x125/+2.50
-3.50/-2.25x050/+2.00

Essentially, these lenses are individually custom-designed. I understand they use mold shaped by computer-controlled machinery to form them, and it takes a lot of math to write the code for each prescription.

There have been great strides in contact lens technology. But not everyone can tolerate contacts, either. Some days I can wear them for 16 hours, other days it's 8 hours. Depending on one's tolerance for the lenses and other factors like spring and fall allergies, it's probably a good idea to keep a pair of regular glasses in the flight bag if the contacts become problematic.

 

[rottydaddy]

Maybe I just haven't found the right pair of cheap shades, but I can't fly, or drive, comfortably with cheap shades. They don't have to be stupid expensive, just not cheap. Got my current Ray-Bans on sale for $100 and they are still hanging in there after 3 years of abuse. I just like the way the world looks thru those things in general, and they are very good for seeing better on those hazy days or in high-glare conditions.

 

[Bob Noel]

But what I meant by 'even' numbers didn't come out quite right. As in your prescription, all numbers are in factors of .25, .5, 125, 50. Mine has numbers like -1.62, x009, x016. I don't know if that's something that contacts can be made in, or if they'd have to be rounded off to -1.60, x010, x015.

And the steps in 'strength' change as it increases. I can get -5.50, -5.75, -6.00, and -6.50, but not -6.25.

 

[Jtmoses]

OK - so, what about Rx sunglasses?

Because of my astigmatism, I've had problems with contacts. Just can't get the same clarity as with glasses, so I've stuck with the spectacles.

I've tried Rx sunglasses, but then I have to swap the sunglasses and regular back and forth and that's a pain. I've tried the photogray a couple decades ago, maybe the chemistry has gotten better over the years, but they've always been a problem in a car or other area that blocks the UV necessary for the lenses to darken. Now, I wear my regular glasses with clip-ons.

Anybody else had any better success in this area?

Recently, I started using Cocoon sunglasses which fit over regular glasses. Inexpensive, varying degrees of light transmittance, non-polarized, choice of filters and styles and available at Amazon. So far, I'm satisfied.