Eyewear Information

Why you should wear sunglasses

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. Long term exposure is linked to eye health issues like cancer of the eye lids, cataracts and macular degeneration. As the eye cannot see UVR, sunglasses have an important function in blocking UVR. Wearing cheap sunglasses with no UV filters poses an even greater danger than wearing none at all because the pupils will dilate allowing more harmful rays into the eye. Good quality sunglasses filter out both UVA and UVB rays, the latter responsible for causing sunburn and eye tissue damage with prolonged, unprotected exposure. Good quality sunglasses should have a UV400 rating providing the maximum protection from harmful UVR. All the sunglasses and eyewear we sell meet this standard.

 Top 5 reasons to wear sunglasses

  • 90 percent of all skin cancers occur above the neck and up to 10 percent of all skin cancers occur on the eyelids. Wearing sunglasses with 100% protection from UVR will not only protect your eyes but also the skin around them.
  • Cataracts – a clouding of the lens in the eye that reduces vision – are a common ailment, particularly as people age. Cataract surgery is the most common operation carried out by the British National Health Service with 400,000 such operations every year. Wearing sunglasses, especially from a young age, will limit the progression of this ailment that can ultimately lead to blindness.
  • They help keep a youthful appearance – wearing sunglasses will prevent squinting and stop wrinkles and crow’s feet from developing around the eyes.
  • In the UK alone about 70,000 new cases of age-related macular degeneration (AMD) are reported every year. AMD causes progressive deterioration of the central area of the retina and according to the RNIB, the British charity for the blind, it’s by far the leading cause of blindness in adults in the UK. The simple precaution of wearing sunglasses with a UV filter will help prevent AMD later in life.
  • Keeping safe in the car – low sun in the sky or the harsh glare experienced when sun strikes a road after rain can be dangerous and around 3,900 road users a year in the UK alone are injured during incidents where the driver had been dazzled by the sun. Keeping a pair of polarized driving sunglasses ready to hand in the car will help drivers deal with these driving hazards.

What the frame measurement means

In the description for each model we have provided the frame & lens size – these are shown as 3 figures e.g. 54-18-137. These figures are the sizes of the frame & lenses measured in millimetres. The sequence means:

Lens width – Bridge width – Overall length of the arm (temple).


Therefore in the figures above:

54 = Lens width

18 = Bridge width

137 = Temple length      

These figures are less important with sports style frames because they are closer fitting and tend to fit a wider variety of head and face shapes.

What does polarization mean?

Light is made of particles called photons, which travel through the atmosphere like a wave, zig-zagging back and forth on their way to your eye. Natural, unpolarized light consists of photons bouncing in many directions at once. But as soon as they strike a surface like a road or water they begin vibrating in one direction, usually horizontally. This is called polarized light and it’s this harsh concentrated light – glare – that make it difficult to see and uncomfortable for your eyes.

The polarizing filters used in polarized sunglasses absorb these horizontally-vibrating waves that reflect off a surface. Meaning only vertically-vibrating waves get through the filter and reach your eye. This greatly reduces the intensity of reflective glare.

Non polarized sunglasses only reduce the amount of light entering the eye; they don’t block glare. Glare not only makes it difficult and uncomfortable to see but causes eye strain. It also distorts the true colour of objects and makes them harder to distinguish. With polarized sunglasses you get glare-free vision, clear contrasts, more natural colours and reduced eye strain or fatigue. Glare also causes a mirror-effect on water. As a polarized lens will eliminate glare on the water it reduces eye strain and means you will be able to see down below the surface.

Because polarized lenses block glare reflected off a surface and improve vision they are popular for many sports and activities including sailing, boating & watersports, fishing, skiing, running, cycling and driving.

It’s worth noting that whilst there are many benefits to wearing polarized sunglasses they can have an effect on some screens. They can reduce the visibility of images produced by liquid crystal displays (LCDs) or light-emitting diode displays (LEDs) found on the instrument panels of aircrafts and dashboards of older cars, or in other places such as the digital screens on automatic teller machines (ATMs) and self-service petrol pumps. With polarized lenses, you also may be unable to see your smartphone or GPS device.

What eyewear frames are made of

Broadly, sunglass frames are either made from plastic or metal. Generally, sports frames use one of the plastics and leisure styles use both metal and plastic. There are several types of plastic frame materials, the two most common being zylonite (zyl) also known as celluloid. It’s an easy material for factories to work with, not expensive and can come in a huge range of colours. The most popular frame material used for sports frames is polycarbonate. The polycarbonate used to make frames is different to that used for lenses, the latter being a much higher grade “pure form” to create optical quality lenses. Polycarbonate for frames is favoured because it’s lightweight but it can be prone to fracture in extreme weather (heat or cold). For both sports and leisure frames a lot of brands are switching over to using a material called Grilamid TR90, a type of nylon because it’s very light but very strong – almost unbreakable.

The non-plastic frames typically used in leisure style sunglasses (including aviator sunglasses) use high-strength, lightweight metal materials choosing either nickel, stainless steel, aluminium or titanium, the latter a premium grade metal that’s ultra-light but incredibly strong. Most brands play safe and use nickel-free metals as sensitive skin can react to nickel.

How polarized lens colours differ

The most popular lens colour. It reduces all light equally, does not increase contrast or alter the colour of objects and is best used in bright and sunny weather.

‘Smoke’ is mostly used as the lens base colour when a mirror finish is applied to the lens. It is similar to grey but can have a brown or blue hue.

Amber & Brown
Popular colours that increase contrast (field of vision will appear sharper), they provide a warm appearance and work well where judging distance is important (like golf). Good all-round colours suited to most weather / light conditions.

A light enhancing colour – good for low visibility, dark, hazy and cloudy conditions. Can help when driving at night especially to cut headlight glare. Provides exceptional contrast and enhanced depth perception. Not suitable in strong sun or high glare conditions.

Some popular eyewear terms and what they mean 

AR coatings – Anti-Reflective coatings eliminate reflections on lenses and help reduce glare, improve overall vision and help in low and poor light conditions.

Clip-on – A pair of sunglass lenses that use a clip to attach to spectacles converting them into a sunglass.

Contrast – The difference in brightness between the light and dark parts of an image. A higher contrast lens (such as yellow) 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.

CR39 – A lightweight plastic lens material now universally favoured by opticians to make prescription lenses for spectacles and sunglasses.

G15 – A grey-green lens colour made popular by Ray-Ban and used in their classic aviator sunglass. A good alternative to plain grey.

Lens categories – The lens category number (Cat. 0 to Cat. 4) equates to a percentage of the VLT (Visible Light Transmission) i.e. 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

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.

Over Glasses – Over glasses are purpose deigned to fit over a pair of spectacles providing sunglass lenses. They typically come with polarised lenses. The term OTG (Over The Glass) is used to describe ski and other goggles that will fit over spectacles.

Photochromic – Lenses that automatically adjust to different light conditions for example going from a light tint in poor/low light to a dark tint in strong sun. The change in tint can take up to 60 seconds. Originally only possibly with glass lenses but now widely available in polycarbonate and Trivex lenses.

Polarized lenses – Polarized lenses are different to standard sunglass lenses; they have a special film (either applied to the front of the lens or embedded in the lens) which helps eliminate glare reflected off a surface like a pavement, road, water or snow. Because polarised lenses block glare off a surface they are popular with sailing, boating and watersports enthusiasts, fishing enthusiasts, snow sports enthusiasts, runners, cyclists and drivers.

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.

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 European CE Mark sunglasses must be UV400 rated. Hence the marking on most 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 but most manufacturers also apply a UV filter. See also UV400.

Back to the top