Editing Sunglasses (section)

=== Land vehicle driving ===
[[File:Hst-by-rsexton-longbeach-5-1989-1.jpg|thumb|right|[[Hunter S. Thompson]] was known for wearing yellow-tinted driving glasses.]] When driving a vehicle, particularly at high speed, dazzling glare caused by a low Sun, or by lights reflecting off snow, puddles, other vehicles, or even the front of the vehicle, can be lethal. Sunglasses can protect against glare when driving. Two criteria must be met: vision must be clear, and the glasses must let sufficient light get to the eyes for the driving conditions. General-purpose sunglasses may be too dark, or otherwise unsuitable for driving.

[[The Automobile Association]] and the [[Federation of Manufacturing Opticians]] have produced guidance for selection of sunglasses for driving. Variable tint or photochromic lenses increase their optical density when exposed to UV light, reverting to their clear state when the UV brightness decreases.  Car windscreens filter out UV light,<ref>[https://www.theglobeandmail.com/globe-drive/culture/commuting/does-my-windshield-protect-me-from-the-sun/article12495123/ The Globe and Mail] {{webarchive|url=https://web.archive.org/web/20170406201410/http://www.theglobeandmail.com/globe-drive/culture/commuting/does-my-windshield-protect-me-from-the-sun/article12495123/ |date=2017-04-06 }}, "Does my windshield protect me from the sun?", retrieved 6 April 2017</ref><ref>{{cite web|url=http://www.autoblog.com/2013/09/06/not-all-car-windows-protect-against-uv-rays/|title=Not All Car Windows Protect Against UV Rays|website=autoblog.com|date=6 September 2013 |access-date=6 April 2017|url-status=live|archive-url=https://web.archive.org/web/20170406201538/http://www.autoblog.com/2013/09/06/not-all-car-windows-protect-against-uv-rays/|archive-date=6 April 2017}}</ref> slowing and limiting the reaction of the lenses and making them unsuitable for driving as they could become too dark or too light for the conditions. Some manufacturers produce special photochromic lenses that adapt to the varying light conditions when driving.

Lenses of fixed tint are graded according to the optical density of the tint; in the UK sunglasses must be labelled and show the filter category number. Lenses with light transmission less than 75% are unsuitable for night driving, and lenses with light transmission less than 8% (category 4) are unsuitable for driving at any time; they should by UK law be labelled 'Not suitable for driving and road use'. Yellow tinted lenses are also not recommended for night use. Due to the light levels within the car, filter category 2 lenses which transmit between 18% and 43% of light are recommended for daytime driving. Polarised lenses normally have a fixed tint, and can reduce reflected glare more than non-polarised lenses of the same density, particularly on wet roads.

Graduated lenses, with the bottom part lighter than the top, can make it easier to see the controls within the car. All sunglasses should be marked as meeting the standard for the region where sold. An [[anti-reflection coating]] is recommended, and a hard coating to protect the lenses from scratches. Sunglasses with deep side arms can block side, or peripheral, vision and are not recommended for driving.<ref>{{Cite web|url=https://www.theaa.com/about-us/public-affairs|archive-url=https://web.archive.org/web/20160415211919/http://www.theaa.com/public_affairs/reports/driving-in-sunglasses.html|url-status=dead|title=Public affairs &#124; AA|archive-date=April 15, 2016|website=www.theaa.com|access-date=Jun 24, 2020}}</ref><!--ref for all the vehicle section-->

Even though some of these glasses are proven good enough for driving at night, it is strongly recommended not to do so, due to the changes in a wide variety of light intensities, especially while using yellow tinted protection glasses. The main purpose of these glasses are to protect the wearer from dust and smog particles entering into the eyes while driving at high speeds.