Lenses for use in sunny conditions are available in more options than you may realise.
Tinted Lenses are made by putting an ordinary clear lens into a dye, the longer the lens is left in the dye the darker it will be. The lens will the remain at that opacity permanently (the tint mat fade very slightly over a period of years.) Tinted lenses are available in a wide range of colours but only a shade with a mixture of all the primary colours such as grey brown or dark green can be classed as a sunglass everything else is just a cosmetic tint.
Polarised Lenses Polarised lenses are also a permanent dark sunglass lens type but unlike ordinary tinted lenses they will eliminate glare from horizontal surfaces such as road, water or snow, even the dash board of your car. They perform much better than regular sunglass tinted lenses giving you less colour distortion and much clearer vision in bright conditions. We have all been in that situation in the car in the winter months when the tarmac is wet and the sun is low in the sky right in front of you making driving very difficult. A polarised lens will cut out almost all (99.9%) of that type of glare opening up the road ahead.
They are excelent for fishermen too! You will be surprised how well you can see in the water with a polarised lens.
Photochromic lenses have had a number of names over the years. You may be more familiar with terms such as Reactolite, Transitions or Sunsensors amongst others. These are all brand names for the photochromic lens type. This lens will adapt to different light conditions, going dark when outside in daylight then becoming lighter when indoors. The reaction takes place when the lens is exposed to UV light. It is for this reason that the reaction is compromised when in the car because the glass in you car windscreen will filter some of the UV.
Drivewear The Transitions brand have realised the problem for drivers and have developed a whole new lens that combines the benefits of both photochromic lenses and polarised lenses. Here's what they say about the lens
“In the past, clear eyewear was enough. In bright light conditions, polarized sunwear was enough. This is no longer true. Today our lives are strongly influenced by the automobile, which has changed the way we experience the outdoors. We need a third category of lenses in our modern, automobile-centered world. Drivewear.
Drivewear lenses are capable of sensing and reacting to varying light conditions both outside and behind the windshield of the car. From bright sunlight accompanied by intense, blinding glare, to overcast inclement conditions, Drivewear lenses provide the wearer with the appropriate visual solution.
Drivewear lenses provide glare protection through polarization and enhance and protect vision through photochromics which respond to both visible and UV light. By combining the strengths of two of the most important technologies in eyewear today we have developed the lens of tomorrow, Drivewear. “