When choosing the most suitable lenses for their sports eyewear, a number of our customers get confused by the difference between the terms Photochromic and Polarized – two similar sounding terms with quite different lens properties!
Photochromic lenses are light-reactive. They darken when exposed to UV light so the brighter the sunshine the stronger the tint. Indoors, the lenses go virtually clear.
The advantage of photochromic lenses is that you may not need separate filters for different light conditions. It is worth noting that they are affected by temperature, going darker outdoors in cold conditions, which can make them popular for skiiers. Cold lenses will also take longer to go clear when you go inside. Conversely, if you go to hotter climates, photochromic lenses won’t get as dark in sunny conditions.
There are two potential disadvantages to this type of lens, which may or may not be critical, depending on your intended use for the eyewear. First, as the lenses need UV light to work, the light-reactive effect will not work when you are inside a car, so they are not suitable for drivers. Second, the lenses typically take 1 to 2 minutes to change from fully dark to clear when going indoors.
Polarized lenses are normally of fixed tint. They have a polarizing filter which acts like a venetian blind to reduce glare. They are ideal for outdoor daytime uses ranging from skiing to cycling, fishing to watersports, and of course for driving in sunny conditions. They are particularly effective over other types of lens for cutting down on glare from reflective surfaces such as snow, ice, water, and wet roads.
If you wear prescription glasses, the best way to benefit from polarized lenses without breaking the bank is to get a decent pair of clip on sunglasses.