UKC

I'm looking to get some sunglasses that will take a clip in prescription. Main use will be summer Alps climbing and winter skiing. Have found a brand in local cycling shop (Rudy Project) but struggling to decide which lenses to get. Advice would be welcome on these points:

- polarised - essential or not?

- light transmision - RP range from 37 to 6%, Alpine sun would obviously need something at the lower end of the scale but there's nothing between 20% & 6%. What do you recommend?

- uv protection - all RP lenses are 400 uv. Is this enough?

Rich

In reply to Rich C1:

not sure about the prescription stuff, but i have just got myself a pair of julbo explorer chameleons, they are polarised and photochromatic.

being polarised they do reduce glare quite a bit when look at shiney things, cant say how useful this is as i haven't had them on for a prolonged period, but it doesn't do any harm put it that way.

i did a lot of research when looking for my glacier glasses, and discovered...

400nm filtering, is the same as saying 100% filtering of uv.
there are 3 categories, i cant remeber exactly but they range from something like; uv-c 0-150, uv-b 151-300, uv,a 301-400.

the ozone filters out almost all uv-c, most of uv-b, so its uv-a you need to worry about; and as long as the glasses filter up to 400nm of uv its all good.

please dont quote me on the exact figures and categories, but as long as its 400nm its 100% uv filtered.

do some searching on here and google, there were a few companies that kept coming up mentioning prescription glasses when i was researching my own (non-prescription glasses).

In reply to ryedubs: cheers, much appreciated. That sorts out one of the questions. Anyone else out there got any useful tips - particularly about the % of light transmission.

In reply to Rich C1:

Any reason why you are not getting prescription sunnies? I know that Oakley for instance do prescription on all their lenses - then you just need to work out which lense... saves faffing with clip-ins

In reply to balmybaldwin:

i was going to say, i think a lot of the main brands like Cebe, Oakley, Julbo etc, offer this service on at least a few pairs of specs each

In reply to Rich C1:

just thought i better add, % of light transmision is different to UV i think.

say you had dark glasses that filterd out the bright light but had no UV filter, this would actually be bad for your eyes; as you pupils open up because it is dark, therefore letting in more uv because although the lenses are filtering out visible light, they do not filter out UV. if you get my drift. so in reality, glasses that do not filter out UV but are tinted, can cause more UV to enter the eye than wearing none at all.

so really what you want it is, %100 / 400nm uv filtering, and then pick what category of glasses (0,1,2,3,4) you want depending on the activity you shall be doing.

if its for the alps, then most people go with a 3 or a 4. you're better with a 4 for longer durations at high altitude. but then as you descend, or if the whether is overcast, you may not be able to as well with a 4.

you can get photchromatic lenses that change from varying categories too, depedning on the levels of UV. however these too have their floors, as sometimes, the uv is low so they are not so dark, but the light intenstiy is high, or the UV could be high so they are very dark, but the visitbility poor and you cannot see much.

also, one of the most important things to remember is that the glasses should come with side shields to protect from the reflected light getting in and around the edges of your sungigs. and there's no substitue for trying the sungigs on to see if they close around your face propery.

just thought i better add the bit about visible light and UV being different just incase you didn't know.

In reply to Rich C1:

Are you sure about the clip in lenses? Two of the guys I cycle with tried that approach and got fed up with them steaming up (during cycling). They had prescription sunglasses made instead and are both really pleased.

From Optilabs I think

In reply to Rich C1: Thanks for all replies.

I've considered prescription glasses but thought thought these would be more versatile for when I wear contact lenses. My other half has had a pair for a few years and she has never complained about them fogging up.

Ryedubs - % of light transmission does seem to be different to uv and is one of the reasons I started this thread. You mentioned categories of glasses (0,1,2,3,4) but not how they relate to light transmission. The RP glasses I'm looking at go from several with a transmission of about 20% to one lense at 6%. Do you have a reference for how your categories relate to the %?

I'm not keen on photochromatic for the reason you mentioned. Also aware of reflected light and need for side shields / wrap fit - thanks for the reminder though.

In reply to Rich C1:

blimey, now your asking, i only really know what i have picked up by looking about on the net, but here's a copy of a table i found explaining the categories:

protection index(category) / Rate of transmission of visible light
0 / 80% - 100%
1 / 43% - 80%
2 / 18% - 43%
3 / 8% - 18%
4 / 3% - 8%

this table is what i have copied from the Julbo site at this address: http://www.julbousa.com/lenses/

there's a wealth of information on their site, well worth a good view (no pun intended)

remember, that these are the range that a lense has to be in to qualify as a certain category. but there are obviously differences within that too. such as a category 1 lense. that can be 43% or 80%, and as you can appriciate there may be a noticable difference between the two lenses.

HTH anyways, but like i say i'm not an expert.

In reply to ryedubs: Really helpful Ryedubs. Many thanks Rich

In reply to Rich C1: Hi I have a pair of Alpina sunglasses with clip in lenses for the same reasons as you describe, they also have clip in side bits, an elasticated head band, they also come with 3 different types of lenses which can be replaced fairly easily.

Andrew

In reply to Rich C1: I'd go with prescription sunnies, clip ins are heavy and a poor compromise. Depends too on how sensitive your eyes are, I wear cat 3 for driving, cat 4 elsewhere (Different to UV protection iirc), but you might need less or more- and one other, try out polarised lenses before buying presrip ones if you get migraines- as much as I love the anti-glare, Polarised lenses trigger some damned awful migraines for me. But there again I'm a big fluffy ball of wuss.

In reply to Rich C1: Julbo also do a special non fogging finish to some of their sunglasses - they say its the same technology as on F1 drivers helmets. Anyhow it works really well. I have got their Zebra Cat 2 to Cat 4 lenses which work well for UK Summer through to 7000+ mountains.
Tried polarised but found I then couldnt use a digital camera since you can get cross polarisation with the camera LCD screen.
Bigest problem was trying to find really strong sun glasses case, most were right size but flimsy or solid but far too big.

In reply to ian2u:

good point, i have the julbo explorers, (only recently mind) and they have the magical mystical anti fog finnish, i agree it is really affective, although i haven't used them in ager yet.

i find that the polarised lenses do create problems when looking at lcd screens, something to do with the fact that the screens us their own filter of some sort or another right?? bit i find unless i tilt my head to the side, or tilt the camera (thus aligning/overlapping the two filters), the image is not interfered with at all, my camera was excaviated from a pyramid about a million years ago so maybe its an older gadget, i dont know?

so be careful if you want to use the specs for driving and you have a heads up display in the car that is lcd, or a screen projection display, as i guess these would create blackspots too.

the case that comes with the julbo's is pretty good, mines a grey colour with brown zips, really robust and good sixe, also get a little pull string bag so you can keep other bits in the case (perhaps spare side shields or something) without them sccretching the lenses. its good for cleaning the lenses also.