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If you were a motor car driver in the 1930’s then along with your driving gloves, motoring rug and spare can of petrol you might also have worn these driving spectacles. They came with the following instructions: For Night Driving the revolving discs should be turned to the right…this cuts out the dazzle of oncoming headlights whilst leaving the road clear ahead and a clear view of the near side edge of the road. For driving in sunny weather adjust revolving discs to cut out the glare from whichever direction it appears, viz. – top of either sidei
Drivers today have access to a wide variety of lenses which can give protection against bright, dazzling sunshine but for night driving the best solution for all drivers is to make sure that their head lights, windscreens and mirrors are clean and defect free. Spectacle wearers should ensure that their lenses are scratch free and have an anti-reflective coating.
Many older drivers swear by amber tinted lenses for night time and poor visibility driving because, by enhancing the contrast between light and dark objects, they seem to improve vision. However they are not recommended as in low light levels any tint will reduce the eyes’ ability to see what is happening and will increase the risk of being involved in an accident. The High way code advises against wearing any form of tinted lens at night.
Visit http://www.drivewearlens.com/task.php to learn more about what your eyes have to cope with when driving.
Glasses that are kept in the car just for driving have often seen better days. They maybe an old prescription, the lenses are often scratched or the frame maybe distorted all of which increases visual discomfort and reduces their effectiveness. Plastic lenses which have been left on the dash board in the sun can heat up and distort which will damage any coatings. Cheap sunspecs that do not fit properly can pinch behind the ears or on the nose which causes discomfort or may slip allowing stray sunlight to enter the eyes causing further distraction.
Tinted lenses should protect the eye from harmful radiation, dazzle and glare. All sunspecs need to filter out 99% of UVA/UVB light and carry the CE mark.ii In the car it is not so much the depth of colour that increases comfort but the shade and quality of tint. The effectiveness of any tinted lens to give comfortable vision depends on the quality of the lens material and its coating. Cheap coatings can lead to fatigue, headaches and eyestrain all of which reduce the driver’s ability to concentrate.
Visit http://www.drivewearlens.com/effect.php to see for your self how specialist lenses could improve your driving vision.
There is no perfect answer as to the best specs for driving; it all depends on the conditions – which are constantly changing. Anything is a compromise. Dark lenses that protect well from bright glare can reduce the eyes sensitivity when driving in tree lined avenues to into poorly lit tunnels. Non-spec wearers can compensate by removing sunspecs, but they often end up on the passenger seat or floor from where they can not be safely retrieved when glare again becomes a problem. Spectacle wearers can not switch from sun glasses to clear prescription glasses as the need arises.
A good compromise used to be Photochromic lenses. Older types had a residual tint which offered some protection in the car for daytime driving. Unfortunately modern Transitioniii lenses, although quicker to react when stepping outside on a bright sunny day, do not hold a residual tint and do not react to sunlight when sitting behind a car windscreen.
Polarised lenses work best when protection is needed from reflected glare e.g. light which is reflected off wet roads, but can be too dark for general driving conditions. Traditionally 
shades of browns and green iv have been popular colours for ‘Sunnies’ but recent research suggests that they should not be recommended for drivers
with a colour vision problem.v. Shades of grey work well for driving specs as they are colour perception neutral, but blue tinted lenses should not be worn when driving as they can do strange things to our perception of the world.
Visit http://www.drivewearlens.com/home.php?flashchange=8 for a demonstration of the lenses you could be wearing whether you need prescription driving specs or just want a pair of sunspecs.
If you live in the Essex area
Visit http://chelmervillageopticians.co.uk for where to go for advice on your driving specs.
i http://www.college-optometrists.org/index.aspx/pcms/site.college.What_We_Do.museyeum.online_exhibitions.spectacles.driving/
ii The CE marking certifies that a product has met EU consumer safety, health or environmental requirements.
v Colour vision is not a bar to driving, but drivers do need to know if they are colour defective. Having a colour vision defect can make it more difficult to see brake lights in conditions of poor visibility and may make it more difficult to read traffic lights.