When light is visibly too strong it makes us blink and reach for our sunglasses. However, when the sky is thinly clouded, the light is not so strong and we blink less frequently. But, the eyes can be exposed considerably to more UVB than in fine weather.
A tinted lens stops all visible rays and will prevent glare, but if it does not include a filter, it will not stop invisible UV rays, which can be harmful to the eyes. It is therefore important for this lens to also incorporate a total UV filter. Sunglasses featuring an adequate UV filter are the best way of protecting the eyes.
In addition to stopping all UV rays, these lenses block glare caused by light reflected from shiny surfaces. They significantly reduce reflections from flat surfaces such as water, ice, snow or sand (beach & dessert) and even shiny surfaces such as the car hood while driving. This enables them to combine visual comfort and safety for all outdoor activities, whatever the light conditions may be.
The many different activities of contemporary life – at work or at play, in town or in the country, in the mountains or on the beach – mean we are subjected to frequent and often sudden variations in light intensity. For example, when stepping outdoors on a bright day, passing through a succession of light and shaded areas or under contrasted skies. Perfectly adapted to these new demands, the latest generation of photochromic lenses provide the best solution to consumers’ wants and needs. Their degree of tint automatically adapts to prevailing light conditions by means of photosensitive molecules incorporated into the lenses.
The worldwide solar protection category standards have been designed to ensure wearers can rely on the safety and visual performance quality provided by sun lenses.
Five categories have been defined (ranked from 0 to 4).
Consult a professional for more information.