Frequently Asked Questions


What does “25” means as in “E-SPF 25”?

The E-SPF value indicates how many times more the lens protects your eyes from UV versus no protection at all.

As a result, E-SPF = 25 means the eye is 25 times better protected than without any lens.

(The Eye-Sun Protection Factor excludes direct eye exposure from around the lenses, that depends on external factors (wearer's morphology, frame shape, position of wear...)

How is the E-SPF for the eye similar to the SPF for skincare?

In the skincare industry, the Sun Protection Factor (SPF) describes the level of skin protection of a sunscreen against the dangers of UV. The SPF number indicates how many times better protected you are with the sunscreen compared to without it.

In the same way, the Eye Sun Protection Factor (E-SPF) describes the full protection of a lens. Not only taking into account UV coming from the front and transmitted through the lens BUT also the biggest remaining danger: UV rays coming from the back and reflected into the eyes by the rear surface of the lens.

The E-SPF value indicates how many times more the lens protects your eyes from UV versus no protection at all.

Is a higher E-SPF related to the dark tint of the lens?

No, even if some sun lenses have an E-SPF of 50+, it is not linked to the tint of the lens.
It is the Anti-Reflective quality which provides a better protection, not the tint.

For sun lenses, you can ask your eye-care professional for corrective sunglasses with an antireflective coating specifically designed for sun lenses and maximizing UV protection, to get an E-SPF of 50+.

Why was the E-SPF created?

Sun protection is part of eye health considerations, and as such, Essilor International strongly believes that a UV indicator is a key requirement for our customers and consumers when choosing a lens. More than two-thirds of consumers are unaware that clear lenses offer any protection against UV! Over 90% of consumers recognized the utility of a sun protection factor for eyewear.(1) 


E-SPF has been developed:

  • To help Eye-Care Professionals choose the right protection for their patients.
  • To help eyeglass wearers make better purchasing decisions  
  • To raise consumer awareness regarding UV dangers to the eyes.


(1) Ipsos Omnibus survey Base: 5000 respondents in 5 European countries (France, Germany, UK, Italy, Spain) 2011.

Does the E-SPF consider both UVA and UVB?

Yes, the E-SPF considers two parameters (Transmission and Reflection) for which the calculation process integrates the requirements of the international norm ISO 8980-3 considering UVA and UVB toxicity.

What about “100% UVA/UVB” protection?

The industry used to only take into account the transmitted UV (front side of the lens) when describing a lens' protection against UV rays. Therefore, the common way to inform customers is to use the “100% UV’’ claim, a protection at 380 nanometres. (Norm ISO 8980-3). It remains valid but it is only one parameter of the lens' UV protection. Essilor International now wants to consider the complete protection of a lens, knowing now that a significant part of visible and UV light can be reflected into the eye by the rear lens surface (the importance of rear surface UV reflection was recently emphasized by K. Citek in 2008*).
The Eye-Sun Protection Factor has been developed as an overall protection index of a lens, integrating for the first time UV protection on both sides.


[ "100%UV Protection" / Depends on the lens material or the technology (Polarized, Photochromic) but not on the tint]

[ Newly recognized hazard, Depends on the rear side coating ]

* Anti-reflective coatings reflect ultraviolet radiation. K.Citek  Sources: Optometry. 2008 Mar; 79(3):143-8.

Lens UV Protection

How can a transparent lens protect me from UV?

UV protection is not a matter of tint. A clear material can block UV transmission.
For instance, windows are transparent and cut most of UV light.
A material is transparent for its ability to let visible light pass through it. A material is perceived as tinted by our eyes because it cuts some visible light. The darker a lens is, the more visible light is stopped. But it is not necessarily associated to a better UV filter.
By definition, UV radiations are invisible, so the ability of a material to stop UV is not apparent to the human eye.
UV absorption is possible by using specific chemicals in lenses that will absorb UV but leave the lenses perfectly transparent.

What about people not wearing eyeglasses?

Yes, people not wearing eyeglasses are more exposed.

UV dangers for the eye have been proven by scientific research. UV rays also impact the skin, provoking premature aging, and are linked to some skin cancers. The skin around the eyes is particularly sensitive.

People not wearing eyeglasses are "solely" exposed to direct UV light, for which the eye has some level of natural protection (squinting, turning, pupil contraction, etc.) . There is no reflection, so no insidious UV rays coming from the back and sides for non-wearers.

For them, Essilor International highly recommends wearing non-corrective 100% UVA/UVB sunglasses as often as possible. This is especially true for children!

Is there any evidence that clear lenses can slow down the development of cataracts?

Yes, it has been known for a long time that clear lenses already contribute to slowing down cataracts, thanks to their existing level of UV protection.
By significantly increasing UV protection of the wearers' eyes, E-SPF 25 lenses should contribute to preserving eye health even longer.

May I wear my usual corrective clear glasses as a regular protection against the sun?

 UV protective eyeglasses cannot replace a pair of sunglasses.

  • Firstly, because eyeglasses will not provide you with the same visual comfort as they stop neither bright light nor polarized dazzling light. 
  • Secondly, because sunglass frames are usually larger and will better block UV rays coming from the back and sides, minimizing reflections into the eyes. 

Essilor recommends 100% UVA/UVB sunglasses which can be adapted to your sight if you are a regular wearer of corrective eyeglasses. Ask your Eye-Care Professional for advice.

UV Hazards

Why are UV rays a real danger to the eyes?

UV rays are invisible, are present everywhere, and are harmful all year round.

  • UV exposure concerns everyone.
  • There is no amount of UV exposure that is healthy for the eyes. 
  • Over 40% of annual UV exposure is received during conditions when we are not in full sunlight and less likely to wear protection.(1)
  • In almost half of your daily activities, such as running errands or walking the dog, your eyes are susceptible to harmful UV rays. UV radiations mainly come from the sun but they also come from elsewhere, as they are scattered by clouds and reflected by many surrounding surfaces. This indirect radiation is responsible for nearly half of the UV radiations we receive(2).

Chronic exposure to the ultraviolet radiation in sunlight has been implicated in a number of ocular diseases including ptegeryum, cataracts, pinguecula and climatic keratopathy; and recent research has uncovered new, unexpected risks to the eyes.

(1) Calculation based on urban workers in northern hemisphere. Indoor low emission from compact fluorescent light bulbs.
(2) Baldy C, Greenstein V, Holopigian K, et al. Light, Sight, and Photochromics. Pinellas Park, Florida: Transitions Optical Inc. 2002.

Why UV rays are dangerous for the skin around the eyes?

90% of skin cancers occurs on the face and neck, of which 5% to 10% around the eye.

UV radiations are classified as a human carcinogen, implicated in the development of skin cancer (melanoma and non-melanoma), premature aging of the skin and other skin problems, and have been recognized as a risk factor for the immune system. The skin around the eye is particularly sensitive.

UVBs are responsible for sunburn while UVAs penetrate into the deepest layers of the skin. Both are equally harmful and lead to cumulative damage that can be very serious.

Taking a few sensible precautions and understanding these risks will help you enjoy the sun while lowering your chances of sun-related health problems.