We already know the Sun Protection Factor (SPF) of sunscreen but, do you know that there is an equivalent for eyeglasses?
The Eye-Sun Protection Factor (E-SPF) is an index developed by Essilor, the world leader of lenses. This index has been supported by everyone in the optical domain as the standard way of certifying the global UV protection of a lens.
In order to determine the level of protection, a measuring protocol, which has into consideration the global protection of each lens, must be followed. In many occasions the ‘100% protection against UV’ label just makes reference to the blocking UV radiation property of the lens. Nevertheless, there is a part of the UV radiation that provokes reflections in the following part and in the side part of the lens. However, not all the lenses provide full protection against these reflections. For that reason, the E-SPF index takes into consideration the degree of UV protection, either with light that passes through the lens or the light reflected in the following part of the lens.
The E-SPF system can be used for any eyeglasses brand and any type of UV protection. Besides it helps consumers and opticians better evaluate the level of protection that a lens offers their eyes and to choose the lens that fits better with each person.
Invisibles effects of UV radiation
In the next video, by means of an UV camera, we can discover the real effects of avoiding the use of protection against this type of radiation:
We have already seen the importance of using a proper protection. Finally, we recommend you to use sunglasses or prescription glasses with UV protection.
