Photochromic sunglasses

Photochromic sun glasses, where the lens darkens as the light intensity increases are a useful compromise but two things to remember about them. Firstly, they response to UVA light and since that is absorbed by a car windscreen these lenses do not go very dark inside a car.

Secondly, they are not very subtle in their light response and even in a Scottish winter dull day these lenses will look to others like sunspecs - maybe a bit pretentious? Therefore, think of photochromic lenses as a very useful second pair of spectacles, great abroad by the pool, popping in to the hotel for another book to read without changing the specs but not as your only pair.

Photochromic lenses are available in brown or grey, single vision, bifocal or varifocal as well as some thin designs for higher prescriptions. Neutral grey, amber, brown or green lenses are good choices as they have less effect on the way we see colours, while some pink or blue tints can distort colours and are not recommended for driving.