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Thread ID: 75877	2007-01-13 07:39:00	Sunglasses- anyone know anything about them?	Sick Puppy (6959)	PC World Chat

Post ID	Timestamp	Content	User
515475	2007-01-14 00:47:00	"Name" sunglasses are like cosmetics. The biggest element in the production cost is advertising, followed by the packaging. The actual product could well be sold by the $2 shops, with plenty of markup included. ... Polarised sunglasses ... may make car windscreens look funny with big spots all over them. ... That's because they are acting as the analyser in a polarimeter to show the stress distribution in heat-treated safety glass. The sunlight is polarised (usually horizontally) when it's reflected and the lenses are vertically polarised -- that's how they reduce glare from reflected sunlight, as well as the (up to 50%) reduction in intensity caused by the polarising. Any UV reduction is by absorption.So this would be why Aerial differentiate between polarised and "driver's" glasses then? If I want a pair for driving then I should not get polarised? I think my last pair were erm, photochromatic (nup, dunno what this is either!), but I found they were a but too 'restful' for driving- wanted more contrast, so I figure I will get amber ones this time ... will have a look around tomorrow at lunchtime ...	Sick Puppy (6959)
515476	2007-01-14 00:51:00	Oops, added a repost by mistake! :D So, how do I delete re-posts here? Went to advanced options, couldn't see anything... :blush:	Sick Puppy (6959)
515477	2007-01-14 00:55:00	because in the past some ****** government department made them label them as unsafe for driving due to being too dark, Now they have lightened them up and sell them as driving glasses, I'm sure on a rack the ones designated as unsafe for driving wouldn't be able to compete with glasses designated for driving. All a load of BS, Just rock on up and pick the style and darkness that suits, I'm gutted that I can no longer buy a set of glasses as dark as I prefer them. Ive had about 15 pairs of those aerials as they sell em at the servo I go to, Not only are they the weakest constructed glasses ever made (I had more then one pair jump into pieces simply by putting them in my pocket) but the polarized glasses are not even worth wearing and their drivers glasses are nearly as bad.	Metla (12)
515478	2007-01-14 00:56:00	We found, when I worked at that large hospital in LA that amber (low- or high-pressure sodium) lighting in the parking lots was much better than white (halogen) lighting for security. Amber seems to allow the human eye see motion easier whereas white or near white light has a tendency to confuse the eye/brain and make detecting activities harder to differentiate from still objects. Therefor I use ambers at night or in the fog or overcast days for driving to help spot trouble or danger easier. They also work very well in snow and rain driving. I really don't care much about the UV factor, unless I can see fish better with that option.	SurferJoe46 (51)
515479	2007-01-14 01:19:00	The inventor of "Polaroid" wanted to have headlights polarised, and windscreens polarised. In those days, most safety glass was laminated, not heat treated, so there wasn't any patchy appearance. I don't drive a car, and have rarely used sunglasses, so I'm not sure, but probably plain tinted lenses would be best for driving. [quote=... erm, photochromatic (nup, dunno what this is either!), [/quote] Photochromic lenses contain a dye which darkens depending on brightness. They are sometimes used in prescription glasses, so you don't have to have clipons or an extra tinted pair. The dye depends on the amount of UV, so they can be a nuisance under fluorescent lights inside. But car windows absorb UV, so photochromic sunglasses probably won't be much use as driving glasses. The dyes seem to be temperature dependent, so they're probably not much use as sunglasses out in the sun either. :D	Graham L (2)
515480	2007-01-14 04:07:00	I really don't care much about the UV factor, unless I can see fish better with that option . That is a huge mistake . If you wear tinted or dark sunglasses that are not UV resistant you will do a lot of harm to your eyes . When you are outside without eye protection your pupils naturally constrict to allow less light in to protect them . When you wear dark glasses the pupils of your eyes open wide in order for you to see better like they do at night time . If the glasses are not UV resistant those UV rays will just go straight through into your eyes and burn them . My partner has a bit of a lump on his eyeball that used to cause a bit of irritation . When he went to the specialist about it he was told it wasn't nasty at that stage and had some of it scraped off . The specialist told him that the cause was most likely being out in the boat without sunglasses on and that he should wear good sunnies whilst boating otherwise he could do some serious damage to his eyes eventually .	FoxyMX (5)
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