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Solar: How does E-SPF work?

Optics Professionals: The key moment to sell your sunglasses has arrived. But for the general public, it can be complicated to find among the various protection indices offered by eyewear. To better inform them, Essilor created, a few years ago, the E-SPF: an index inspired by solar cosmetics. We will explain everything to you !

Solar protection: legislation

Sunlight is very harmful to the eyes, especially in the summer, when there is more sunlight .   Among the most serious risks caused by UV rays: aggression of the cornea, lens, or even the retina. But for the general public, in search of sunglasses , it can be difficult to choose the perfect pair of sunglasses. However, it is very important to choose a protection adapted to your environment.

E-SPF sunglasses

Currently, most manufacturers use the degree system to indicate the protection of their sunglasses :

  • Degree 0: for indoors or under cloudy sky
  • Degree 1: for attenuated solar brightness
  • Degree 2: for medium brightness
  • Degree 3: for high brightness
  • Degree 4: for exceptional brightness (in the mountains for example).

Other criteria must also be taken into account: the shape, the marking, and the instructions for the sunglasses.

Solar: E-SPF innovation

The degree system can be complicated to understand for solar wearers. That's why our member Essilor created, a few years ago, the E-SPF (Eye-Sun Protection Factor) marking , which works like solar cosmetics. An E-SPF of 25, for example, means that the wearer is 25 times better protected than without glass. The innovation here is that the index takes into account, in addition to the UV transmission , the reflection of the glass on the back. And this is not negligible, when we know that up to 50% of the total UV exposure of the eye comes from behind!

E-SPF sunglasses

Since 2012, the glassmaker has been integrating its Crizal Forte UV treatment index and has been offering different pairs of sunscreens equipped with this treatment.

E-SPF: white glasses too

But Crizal Forte UV treatment is also available on white lenses . Indeed, an E-SPF of 25 is advised daily by the professionals of the optics. Essilor even launched in 2015 its Crizal UV 35 transparent lenses, the highest UV protection index!

To enable wearers to be permanently protected from the sun, other eyewear companies such as Zeiss have bet on on photochromic lenses (variable shade), which change color depending on the degree of brightness. There are also polarizing lenses , such as those of Optic 2000 , which prevent glare by the effect of reverberation of light and are useful, especially for driving.

So, ready to sell your stock of glasses Sun Creme ? 😉