Understanding the Eye-Sun Protection Factor (E-SPF®)
The Eye-Sun Protection Factor (E-SPF®) is a global index measuring the level of Ultraviolet (UV) protection for eyes. The higher the E-SPF, the higher the amount of UV protection your lenses provide.
E-SPF factors protection from UV light coming from both the front and the back sides of the lens (transmission protection from the lens material and backside reflection protection from the No-Glare coating).
Why is E-SPF different from other UV indexes?
Most UV protection ratings (i.e. 100% UV protection) only factor how well the lenses prevent UV from transmitting through the front of the lens and into the eye. Therefore, these kinds of ratings are only considering a portion of overall UV protection needed for our eyes. Recent research has discovered that UV light reflecting off of the backside of lenses and into the eye can account for on average 20% of our overall ocular UV exposure.
Crizal No-Glare lenses, when made with any lens material (except for clear 1.5 plastic) provide the most complete daily UV protection with an E-SPF of 25, for 25 times more UV protection for your eyes compared to wearing no lenses at all. An E-SPF of 25 is an excellent level for daily UV protection.
When Crizal is paired with a clear 1.5 plastic lens material, the E-SPF drops to 10 because the lens material does not block front side UV transmissions.
With Crizal, it is always recommend using a higher-quality lens material (such as Airwear™ or Thin&Lite™) or Transitions® lenses in order to get the most complete UV protection.
The E-SPF index was created with the consumer-friendly SPF index, used to rate skincare and sunscreen products’ efficiency against UV. The E-SPF index can help you easily explain to patients the level of UV protection their lenses provide when paired with Crizal compared to other ordinary No-Glare brands.
Visit www.ESPF.com to learn more about E-SPF.