Many people ask us what the difference is between polarised and photochromic lenses.
Polarised lenses
A polarised lens reduces glare from the sun that is reflected at an angle off shiny surfaces.
These may include water, light coloured buildings, metal surfaces such as car bonnets, and roads, especially when the sun is at a low angle and glare is is caused by reflection off a wet or icy road surface.
Polarised lenses are generally the preferred choice if your eyes are sensitive to the sun's glare. They are particularly useful for sailing and other water sports, fishing, driving, cycling and generally for people who are sensitive to glare.
Polarised lenses are available in a range of colours - the most popular are grey, brown, and copper.
Photochromic lenses
Photochromic lenses are light-reactive, becoming darker when UV light shines on them.
Normally these lenses are virtually clear indoors and in low light conditions and become a darker tint when you are outdoors. In cloudy weather they may hardly change at all. In bright sunny weather they will change to a darker colour (though not as dark as the polarised lenses - see above).
Because photochromic lenses are activated by UV light they do not react behind a car windscreen or behind a motorcycle helmet visor.
The performance of these lenses depends partly on the air temperature. They change to a darker colour in full sun when used in very cold climates than when in very warm ones.