Sunglasses too dark to drive...

[21TonyK]

Discovered something today. Sunglasses are categorised by the amount of light they allow through on a scale of 0 to 4, 4 being the darkest as found on some sports/cycling glasses. The number is printed on the arm of the glasses.

Its illegal to drive wearing category 4 glasses.

My bog standard sunnies are a 3, yours?

[POIDH]

All... Mine are photochromic 😎

I find in the car that they never go as dark. I think being indoors/under roof they do not catch direct sunlight too often. And if they do and fully darken, it's because of low sun.

[Mr Penguin]

I have prescription aviators for driving, they are at the legal maximum tint which IIRC is around 85%.

[hammo19]

Interesting.

Have the Police got potable sunglasses tint measuring devices attached to their ever growing vest attachments now?

[ARH]

hammo19 said:

Interesting.

Have the Police got potable sunglasses tint measuring devices attached to their ever growing vest attachments now?

When was the last time someone got pulled over by a police car?

They are probably developing a camera to detect the amount of tint as we speak

[ATG]

I've got some category 4 glacier glasses. I would never even think about driving in them because you'd be able to see bugger all. On the brightest days you get in the UK, the outside world would look calmly dim ... it's a bit odd, but relaxing ... but you wouldn't be able to read the dashboard. It's one notch down from wearing a welding visor. If you're in direct sunlight on snow, they're great, because those conditions are far, far brighter than you'll encounter elsewhere.

[snuffy]

I've just bought a pair of Oakley prescription sunglasses, and it says 3 on the prescription itself. And it has a table, where it says 4 is not for driving.

But it's certainly not written on the arms or any part of the frame, but then, how would that work?

[ATG]

I've got photo chromatic lenses in my everyday varifocals and I regret that. A photo chromatic lens respond to UV light. Car windscreens block the sun's UV, so photo chromatic lenses hardly dim at all when you're in the car regardless of how bright the sun is. This makes them pretty useless as "sunglasses" for driving. When you're outside, even in overcast conditions, during daylight hours there will be a fair bit of UV so your glasses will almost always be a bit tinted ... making you look like a sexual deviant, but more importantly it means you don't have the option of seeing colours the way they really are.

I've got some prescription sunglasses and they are far, far better as sunglasses than the photo chromatic ones, so next time I replace the varifocals, I'll go for clear lenses.

[renmure]

I also have a pair of category 4 prescription sunglasses bought quite a few years ago. The optician did warn me about not being able to drive with them but obviously I knew better. I actually think driving would be impossible and even walking around is like being blindfolded. They have lived in a drawer somewhere for years

[vixen1700]

Just checked my prescription shades and they're cat 3. I had no idea about this!

Wear them all the time and find I have to wear them the odd occassion I drive at night because of the glare of modern headlamps.

[twing]

Mine say 3P, guessing the P is for polarized. I rarely drive in them as I can't see a thing as soon as I get under trees, etc

[Shnozz]

ATG said:

I've got photo chromatic lenses in my everyday varifocals and I regret that. A photo chromatic lens respond to UV light. Car windscreens block the sun's UV, so photo chromatic lenses hardly dim at all when you're in the car regardless of how bright the sun is. This makes them pretty useless as "sunglasses" for driving. When you're outside, even in overcast conditions, during daylight hours there will be a fair bit of UV so your glasses will almost always be a bit tinted ... making you look like a sexual deviant, but more importantly it means you don't have the option of seeing colours the way they really are.

I've got some prescription sunglasses and they are far, far better as sunglasses than the photo chromatic ones, so next time I replace the varifocals, I'll go for clear lenses.

What put me off using prescription sunglasses was the odd occasion I was driving somewhere unfamiliar and found myself entering a tunnel. Desperately scrambling for my non shaded prescription glasses was not fun.

Admittedly a rare occasion, particularly in the uk where you’ll usually be aware in advance you will be going through a tunnel, but nonetheless. Terrifying.

[untakenname]

I've got some cat 4's in the sunvisor, not very useful in summer but a godsend when the roads wet and the suns low in winter/spring.

I doubt the police would ever check unless there was a severe accident that was caused by not looking, years ago a guy killed a cyclist by dooring them with a window tint which only allowed 17% light transmission and got away with.

https://www.bbc.co.uk/news/uk-england-london-20725...

Unrelated, but whilst looking for the news article it seems the doorer was shot in a gang related drive by a couple of years back which killed a 9 year old.

[CanAm]

twing said:

Mine say 3P, guessing the P is for polarized. I rarely drive in them as I can't see a thing as soon as I get under trees, etc

Maybe P for photo chromatic, as Polarised lenses have a fixed tint.

[twing]

CanAm said:

Maybe P for photo chromatic, as Polarised lenses have a fixed tint.

Sorry, badly explained. They're only polarized but very dark, which is fine in the sun but totally useless in the shade. On another note I can't see a phone screen properly through them whereas I can in another polarized pair, both made by the same company.

[RDMcG]

I have used Serengeti Drivers for years . Not deeply tinted.

[ATG]

renmure said:

I also have a pair of category 4 prescription sunglasses bought quite a few years ago. The optician did warn me about not being able to drive with them but obviously I knew better. I actually think driving would be impossible and even walking around is like being blindfolded. They have lived in a drawer somewhere for years

There's an eclipse later this year, I think. Time to dig them out!

[snuffy]

CanAm said:

twing said:

Mine say 3P, guessing the P is for polarized. I rarely drive in them as I can't see a thing as soon as I get under trees, etc

Maybe P for photo chromatic, as Polarised lenses have a fixed tint.

On my Oakley prescription sheet, it says:

N = Normal
P = Polarised
F = Photochromatic

[Puddenchucker]

I've got a pair of Cébés I bought about 10 years ago where the accompanying paperwork warns / advises against wearing whilst driving (I can't remember what category they are) but they were fine when I had a convertible with the roof down.

[Actual]

twing said:

Sorry, badly explained. They're only polarized but very dark, which is fine in the sun but totally useless in the shade. On another note I can't see a phone screen properly through them whereas I can in another polarized pair, both made by the same company.

This could be due to a clash of vertical and horizontal polarization.

One only allows vertical wavelength light to pass and the other only allows horizontal wavelength light through (not sure if vertical allows vertical or what).

LCD panels use a polarizer and so the display can be masked by sunglasses.

Another permutation is circular polarisation.

Anyway that is a possibly incorrect technical explanation but that's the gist of it.