Ultraviolet Radiation (UVR)
Evolution, like other good quality sunglasses, eliminate solar ultraviolet radiation (UVR), in particular the more damaging UVB radiation. UV rays from sunlight can damage the retina and the lens of the eye. Too much exposure is linked to conditions like cancer of the eyelids, cataracts and age-related macular degeneration. Sunglasses that provide maximum UVR protection are CE/UKCA marked and UV400 rated: all Evolution sunglasses and eyewear meet this requirement. They will, therefore, provide the eye with substantial protection against solar UVR and reducing the amount of UVR that the eye is exposed to over a person’s lifetime is highly beneficial.
Polarised (Polarized) Sunglasses
Polarised (polarized) lenses are different to standard sunglass lenses; they have a special film either sandwiched between two other layers of the lens or applied to the front of a lens. What this special film does is eliminate the glare reflecting off a surface like a pavement, road, water or snow. Lightwaves from the sun travel in all directions but when sunlight strikes a surface, it becomes polarised (concentrated) resulting in glare; a polarised lens will eliminate this harsh glare. The result is the ability to see light in its pure state. Objects will appear more defined, sharper and naturally coloured. Instead of squinting to minimise glare, a polarised lens will allow your eyes to see colours with true clarity. Because polarised lenses block glare reflected off a surface (road, pavement, water or snow) they are popular with sailing, boating and watersports enthusiasts, fishing enthusiasts, snow sports enthusiasts, runners, cyclists and drivers. When used for fishing a polarised lens means you will be able to see down below the surface of the water.
Although polarised lenses provide lots of vision benefits it is important to note that the majority of polarised lenses (including Evolution polarised lenses) are made from a material called TAC which is relatively thin and does not provide impact protection. For sports such as shooting where impact protection is important a polycarbonate lens is required.
Skiing, hiking or climbing at high altitude
For anyone going skiing, hiking or climbing at high altitude, it’s essential to wear good quality sunglasses or goggles because on mountains the sun’s harmful ultraviolet rays are easily underestimated, with a high risk of sunburn and potentially skin cancer and eye cataracts. Because mountain air is cool, it gives a false sense of security about the sunlight. But the higher the altitude, the greater the ultraviolet (UV) radiation because there is less atmosphere to screen out harmful rays. A study by Japanese scientists revealed that eyes can receive up to 2.5 times more UV on mountains than at sea level. Even when the eyes are turned away from the sun, they can still get over 85 per cent more UV on snow. This can cause conditions such as snow blindness, which can lead to inflammation and cataracts.
Lenses colours and their uses
- Grey – The most popular lens colour it reduces all light equally and does not increase contrast – best for bright light and sunny conditions.
- Smoke – Similar to grey but usually has a blue or brown ‘hue’. It is used as the base colour when a mirror finish is applied to the lens.
- Green / G15 – First popularised by Ray-Ban with their classic aviator sunglasses. Creates a soothing tone and adds contrast; a good alternative to plain grey for bright sun conditions.
- Amber / Brown / Vermilion – Popular colours that give a warm appearance and they increase contrast (objects will appear in sharper focus), suitable for most weather / light conditions.
- Yellow – A light enhancing, high contrast colour ; good for poor light, low visibility, dull or cloudy conditions.
- Clear – For protecting eyes from impact, dust / dirt or abrasion.
- Red / Rose / Orange – High definition lenses that filter out blue light which is known to cause eye strain and fatigue. Give a sharper field of vision and objects will be more clearly defined; good colours for overcast conditions.
- Purple – A great all-round colour that gives a “soothing” appearance. It has also become widely adopted by clay target shooters; known as ‘the background neutraliser’ it dulls a green / brown background and enables the shooter to more clearly see any clay target colour against a dark background. Purple is also becoming a popular colour for golfers.
- Blue – A blue lens can highlight the colour yellow and gold so it can be beneficial to tennis players (yellow ball) and archers (gold bull).
- Mirror lenses – Flash and full mirror are coatings applied to the front of the lens (usually applied to a base ‘smoke’ lens). The ‘Revo’ mirror is where more than one mirror colour is used eg. red-orange. They are primarily for cosmetic effect but also increase the filtering power by reducing the amount of light interference.
The Category number equates to a percentage of the VLT (Visible Light Transmission); how much light the lens lets through, as follows:
Category 0: 80-100% VLT
Category 1: 46-79% VLT
Category 2: 18-45% VLT
Category 3: 8-17% VLT
Category 4: 3-8% VLT
The following is a general guide to the Categories that apply to different lens colours:
Category 0 – Clear, Light Yellow, Pale Orange and Yellow
Category 1 – Orange, Rose & Vermilion
Category 2 – Purple, Red, Amber & Light Brown
Category 3 – ‘Standard’ Grey & Brown
Category 4 – Dark Grey & Dark Brown
Multi Lens Interchangeable Eyewear Sets
These have become very popular because they give a choice of lenses fitting the same frame. They will typically come with at least 3 different lenses such as grey, yellow and orange. It means you can change the lens colour to suit the light and background conditions. Evolution has one of the largest ranges of multi-lens sets of any manufacturer.
Polycarbonate is the lens material favoured by sports eyewear brands like Evolution because it’s very light but shatterproof and impact resistant; providing a very high degree of eye protection: 20 times the impact strength of glass and up to 10 times the impact strength of normal plastic. However, polycarbonate is prone to scratches so it’s important to take care of the lenses and always keep your sunglasses or eyewear in a case or carry pouch when not in use: all Evolution models are supplied with a soft carry pouch and many with a hard case too.
Glossary of Popular Optical Terms
Base curve – The curve of the lens: a base of 4 being relatively flat, up to base 10 being a very pronounced curve.
BS EN ISO 12312-1:2013 – Sunglasses and other eyewear imported, manufactured or sold in the European Union must comply with this standard. Sunglasses are categorised as Personal Protective Equipment (PPE) and the relevant European PPE Directive is EU 2016/425. See also CE & UKCA Marks.
Contrast – The difference in brightness between the light and dark parts of an image. A higher contrast lens (such as yellow and orange) provides a much sharper field of vision.
CE Mark – This means the product complies with relevant EU safety, health and environmental requirements; for ‘general purpose sunglasses’ the relevant standard is BS EN ISO 12312-1:2013. See also: UKCA.
CR39 – A lightweight plastic lens material now universally favoured by opticians to make prescription lenses for spectacles and sunglasses. Limited impact protection.
EN166F / ANSI Z87.1 Standards – European & US (respectively) safety standards that must be met for eyewear to be considered to have projectile impact protection.
Glass / Mineral – Glass lenses (for eyewear also called Mineral), provide the best possible visual experience and high scratch resistance, but they are heavier than plastic and polycarbonate lenses and can shatter, so not for use in sports sunglasses.
Interchangeable lenses – Models with interchangeable lenses (also called Multi-Lens sets) have become very popular because they give a choice of different lens colours fitting the same frame. They will typically come with at least 3 different colour lenses.
Lens colours – Polycarbonate and Trivex lenses can be made in a huge variety of colours. These colours can be used for different light conditions, backgrounds and to help see different target colours e.g. in archery and shooting.
Macular degeneration – A degenerative disease that causes deterioration of the central portion of the retina known as the macula, resulting in loss of vision and even blindness. Wearing sunglasses (with UV filters) from an early age can help prevent this disease.
Mirror, revo mirror & flash mirror coatings – Mirror and mirror-revo are coatings applied to the front of the lens (usually applied to a base ‘smoke’ lens). The term ‘revo’ applies when the mirror has more than one colour e.g. red-orange. Mostly chosen for cosmetic effect they also limit glare and increase the filtering power – this can block an additional 10 – 60 % of visible light for greater comfort in intense, full-sun conditions. A flash mirror finish is not a full mirror effect but gives a slight reflection.
PD Measurement – Pupillary Distance measurement: the distance between the pupils of the eyes, centre to centre, in millimetres. Most people have a PD between 54mm and 74mm. If shown as two numbers, such as 31/31.5, this is the distance from the centre of the nose to each pupil centre. To make prescriptions lenses an optician needs the PD number in additional to normal prescription information.
Polycarbonate – Polycarbonate lenses have very high impact resistance: up to 10 times more than normal plastic and 20 times more than glass. Lightweight, they also have ‘built in’ UV protection. The lens material favoured by all sports eyewear manufacturers.
RX – Short for prescription.
Smoke lenses – ‘Smoke’ is the lens colour typically used as the base colour when a mirror finish is applied to the lens. It is similar to grey but can have a brown or blue hue.
TR90 / Grilamid (nylon) – A rugged, durable, strong, flexible, lightweight material used in sports eyewear frames. Less prone to breaking in extreme temperatures.
UKCA – The UKCA (UK Conformity Assessed) Mark is the new UK product mark required for most products (including eyewear) sold in the UK following the UK’s departure for the European Union. It covers most products that previously required the CE mark. The marking doesn’t apply to existing products – products manufactured and CE-marked before January 1 2021 can still be sold in Britain with a CE marking. Companies selling to both the UK & European Union markets are now likely to apply both UKCA & CE Marks to there products.
Ultraviolet (UV) radiation – Invisible to the eye, prolonged exposure to solar UV radiation (UVR) may result in acute and chronic damage to the skin and eyes. There are two main types of UV rays: UVA and UVB. UVA rays are longer and can cause sun damage that result in aging and wrinkles, whilst UVB rays will cause sunburn and skin cancer.
UV400 – A sunglass that is labelled and / or marked UV400 means they block over 99% of UVR. This rating ensures that all light rays with wavelengths up to 400 nanometres, including both UVA and UVB rays, are blocked out. See also UV filter. To obtain a UKCA / CE Mark sunglasses must be UV400 rated. Hence the marking on sunglasses is usually: CE UV400
UV Index – The UV index, also known as the Ultraviolet Index, is an international system of measuring ultraviolet solar radiation for a specific day and geographical location. The higher the index, the more intense and dangerous to your health the solar radiation is. When the UV Index reaches 3 or more – even on cloudy days – wearing sunglasses is highly advisable, especially for children.
UV Filter – A lens coating, either applied to the front or embedded in the lens, that filters UV radiation. The UV filter is clear so even clear lenses can provide full UV protection. Trivex and polycarbonate lenses naturally block most UV light and do not need the application of a UV coating. See also UV400.