BBC News Online: Health

Warning over coloured shades

Pink, blue, green and other varieties of lenses could distort the wearer's vision and blank out other colours - such as red traffic lights.

The sunglasses market in the UK is now worth around £180m a year and is growing rapidly as they are seen as fashionable as well as functional.

But research by Boots scientists in Nottingham has raised safety concerns after sunny spells across the UK.

Tests found the colour of a red traffic light completely disappears if a driver is wearing blue tinted glasses.

There are fears that this could slow the reaction time of a car or train driver, even if they are aware of the approaching signal.

Boots recommend consumers shopping for new sunglasses should look for the CE mark which guarantees adequate UV protection.

But researchers urge shoppers to remember the possible problems posed by tinted glasses.