Sunglasses have come a long way since they became a stylish accessory in the late 1940's and early 1950's. Due to concern about the effects of ultra violet radiation, they are being purchased and prescribed more for their value as protection against radiation than they are for appearance.
Photo-chromatic lenses darken when out of doors and lighten when worn inside. There is no doubt that this summer photo-chromatic lenses are going to have a big impact on the sunglasses market. This will be particularly so with prescription sunglasses.

Whilst photo-chromatic lenses manufactured from glass have been available for a number of years it has only been possible to obtain them in plastic for the past two or three years. Plastic photo chromatic lenses have two important benefits to offer; they are lighter than glass and they are less likely to break if dropped or if you are involved in some sort of accident when wearing glasses. Some plastic lenses weigh as little as half that of similar glass lenses. They are marketed under the name "Transitions" and will be utilised considerably more during this coming summer.

Generally tinted glasses act as a filter to reduce the amount of glare; importantly they also filter out harmful ultraviolet rays which have been shown to have a long term cumulative adverse effect upon the eye health.
Polarised lenses are great for protection against glare from horizontal surfaces such as sand, water or snow. This makes them particularly suitable for fishing or boating.