All about sunlight
When we’re outdoors, we have the reflex to protect our skin against the sun. But do we always do the same for our eyes? Knowing how to protect our eyes all year round is essential for protecting healthy vision throughout our lives. Find out more about the invisible dangers in sunlight, how best to lower long-term risks to visual health and some of the technologies and solutions helping to safeguard our eyes.
Everything you need to know about UV
Our eyes are exposed to UV radiation 365 days a year, even on cloudy days.
Only half of total UV radiation comes directly from the sun – the rest is transmitted through clouds in the atmosphere and reflected off the surfaces around us like roads, walls, water, snow, sand).
Even with our backs to the sun or in the shade, UV rays can reach our eyes.
Children are particularly sensitive to bright light: they have larger pupils and more transparent ocular media than adults (the cornea, the aqueous humor, the crystalline lens and the vitreous humor). UV radiation may be harmful for the anterior part of the eye: cornea and crystalline lens.
For better road safety, it’s important to protect our eyes while driving, especially to reduce glare that can slow both detection and reaction times.
Natural light from the sun is composed of a visible part of the spectrum – which allows us to see shapes, forms and colors as well as an invisible part made up ultraviolet (UV), high-energy visible light (HEV) and infrared rays. Natural protective mechanisms like eyelashes, blinking, constriction of the pupil are not enough to prevent temporary discomfort of bright sunlight and glare or the potential short-term damage like blurred vision, inflammation and photokeratitis (a painful temporary blindness).
Cumulative exposure to UV from the sun accelerates the aging of the cornea and the crystalline lens and is a risk factor in cataracts.
Eyewear is an everyday and practical solution
To see comfortably and help to preserve our long-term visual health we should protect our eyes, in particular from dazzling light, glare and the cumulative risks of UV exposure.
Eyewear can be an everyday and practical solution. Sunglasses offer visual comfort and protection in sunlight; other types of lenses can also protect our eyes against UV and HEV light – for example photochromic lenses that adapt from clear to dark according to the intensity of light, as well as transparent corrective lenses that help deflect rays from the front and back side of glasses. Read on to find out more about Essilor lens technologies that contribute to safeguarding our eyes.
All about sunglasses
Not every pair of sunglasses is equal. Despite what many people believe, the darkness of a lens has absolutely no effect on its overall UV protection. Many aspects contribute – from the material of a lens, the shape of the frame, the color and other coatings, particularly anti-reflective coatings. Here’s how:
Materials used to make lenses (corrective or sunglasses) have different levels of UV absorbers and thus offer varying levels of UV protection. Some, like polycarbonate, are also more resistant to shocks and thus more adapted to certain sports and outdoor activities.
The shape of a frame, eg wraparound sunglasses, may cover more of the eye and sensitive area around the eye to block out light from the sides and reduce UV rays passing between the frame and your face.
Sun lenses are ranked according to the darkness of their tint in categories from 0 (light tint) to 4 (darkest). Lower ratings are more adapted to weak sunlight; category 4 is designed for extreme sun conditions.
Tints can be a fixed color across the lens, have a gradient color that’s darker at top than bottom, or even adapt to be darker when its brighter (photochromic).
While many people choose sunglass colors for aesthetic reasons, different lens colors can enhance perception in different environments and for different activities.
High-tech sun lenses often include a polarized filter that, in addition to UV protection, contribute to eliminating glare, shield against dazzling light and enhance clarity and contrasts.
How to check if your sun lenses are polarized?
To check if your sun lenses are polarized, hold the sunglasses in front of a computer screen, rotate them 90°. The screen should go dark through the lenses. If the lenses are not polarized, there will be no change.
Corrective lenses with a variable tint are known as photochromic: they adapt their shading to different levels of sunlight and UV. In bright conditions, the lens will darken and in less intense sun it will become lighter while remaining tinted. Some photochromic lenses are also polarized for ultimate visual comfort.
Other coatings that can be added to sun lenses include:
- Mirror – can also increase protection against UV, infrared and HEV light and is recommended for sports activities in extreme sunlight such as skiing and water sports.
- Anti-reflective (AR) – to provide additional UV protection on both sides of the lens, as well as resist water, grease, dirt and scratches for better transparency and clarity.
The higher the E-SPF® Index, the greater the level of UV protection
The E-SPF® index was developed by Essilor in 2012 and endorsed by third party experts to guide consumers on the level of UV protection of a lens. The E-SPF® index measures the UV protection provided by both sides of the lens and ranges from 10 to 50+: the higher the E-SPF® index, the greater the level of UV protection provided by the lens. E-SPF® rating system is used for sun lenses as well as clear lenses.
Essilor technologies that help protect your eyes
Essilor offers many different solutions to effectively protect our eyes against UV rays, bright light or reflected glare and enhance the visual experience of wearers in their outdoors activities. Find out about the advanced technologies at work in some of the Group’s premium eyewear brands.
Costa®: polarized lenses for water lovers
Costa® is a premium brand of polarized prescription and plano sunglasses created by and for water lovers - from professional anglers and sailors to water sports enthusiasts. Costa® patented 580® lenses were designed by in-house light spectrum experts to enhance color and provide the ultimate in light management and protection by:
- absorbing harmful high-energy blue light (HEV) up to 425nm, cutting haze and blur for greater clarity
- blocking harsh yellow light at 580 nm on the visible light spectrum to boost naturally the amounts of red, greens and blues for sharper contrast and higher definition
Colors adapted to usage
By the coast and on the water, light conditions are constantly changing. Costa® sunwear offers seven colors in multiple lens materials and technologies adapted to low light like dawn to extremely bright light with blinding glare.
Costa® prescription sunglasses are made using Waypoint™ digital technology
To enhance the field of view by eliminating the peripheral blur common with wrap sunwear and come in a range of bi-focal, progressive lens designs.
Xperio™: multiple technologies in one lens
Essilor’s Xperio™ prescription sunwear range combines multiple technologies in one lens to ensure the visual comfort and protection of wearers.
Most Xperio™ lenses include a polarized filter to eliminate harsh and sometimes blinding glare that is reflected off surfaces like roads, water or snow.
All Xperio™ lenses benefit from the full range of Essilor’s optical designs to meet individual single vision or progressive visual needs. Essilor color experts have developed the Xperio™ range to offer a broad aesthetic choice of colors, mirror coatings and gradient tints where the tint deepens gradually from top to bottom.
Ophthalmic lens technology
Sun lenses are manufactured with a series of layers to provide UV protection (front and back side), as well as ensure durability and be easy to clean through water, smudge and scratch resistance.
light intelligent lenses
Transitions® adaptive lenses continuously adapt to changing light conditions. When going from indoor to outdoor conditions, Transitions® lenses darken to help your eyes adjust to changing light better than they would on their own.
They block UVA and UVB rays and reduce exposure to harmful blue lights indoors and outdoors.
Daytime light and weather conditions constantly change on the road. Transitions photochromic technology adjusts the color and tint of the lenses as light conditions change while driving, providing ideal color and clarity for driving while removing glare off the road and car hood.
Traditional photochromic lenses do not activate behind the windshield of a car because the windshield blocks most UV light. Transitions® XTRActive® lenses use a proprietary broad-spectrum photochromic dye that reacts to both UV light and visible light so they are able to achieve up to a category 2 darkness while driving. These lenses are also the darkest lens in the Transitions portfolio, providing superior darkness outdoors. They protect against harmful blue light indoors and outdoors from the sun.
 Citek K, Andre B, Butler JJ et al. The Eye and Solar Ultraviolet Radiation: New understandings of the hazards, costs, and prevention of morbidity. Report of a roundtable. June 2011. Calculation based on urban workers in the northern hemisphere.
 Renata Chadyšienė and Aloyzas Girgždys. Ultraviolet Radiation Albedo of Natural Surfaces. Journal of Environmental Engineering and Landscape Management 2008; 16(2):8388.
 2009, ARVO, Zikos G.A. et al., Contrast Sensitivity and Reaction Times with Polarized and Tinted Lenses in a Driving Environment.
 Jarrett and Boulton, 2012, Mol. Aspects Med. ; Marquioni et al., 2015, PP ; Hollyfield, Bonilha et al., 2008, Nat. Med.
 Marie et al., 2018, Cell Death and Disease ; Arnault, Barrau et al., 2013, PlosOne.
 4: Sui et al., 2012, Br. J. Ophthalmol.