Choosing the Correct Colour Sunglasses Lenses is Vital
In order to ensure your eyes perform to the best of their ability in changing light conditions it is essential that you choose the right colour lenses for your sunglasses.
Knowing where to start is sometimes the most difficult challenge for anybody who is looking to purchase sunglasses and actually understanding the benefits of different coloured lenses is vital to making the right choice. Each sunglasses lens tint gives different levels of performance in different light conditions for a variety of uses. However sunglass lenses all have one thing in common, they protect the wearer from harmful ultra violet rays which can cause both long term and short term health issues for your eyes.
For sunny days with high brightness levels, neutral filters or grey smoke tinted lenses are often preferred because they block high levels of visible light without any colour distortion. Green or grey-green (G-15) lenses provide a uniform absorption of colours throughout the spectrum allowing colours to be seen exactly as they are and therefore provide clearer and true vision. Brown lenses also work well in these conditions, particularly in diffused light, and have contrast-enhancing properties but they do cause some minimal colour distortion. These lenses will be rated UV filter category 3.
Amber, copper, orange, rose, pink and vermillion lenses perform best in medium and lower light conditions because they have excellent contrast enhancement properties. This can help you make out shapes and objects more clearly because they filter the blue (hazy) end of the colour spectrum but they do cause colour distortion. These lenses will be rated UV filter category 2.
Yellow lenses have excellent contrast enhancement and depth perception properties. They’re especially effective in flat light, foggy or overcast conditions helping to increase visibility and will be rated UV filter category 0.
For day time driving, copper lenses provide sharper contrast and image definition by filtering blue light and reducing road glare whilst preserving a natural colour balance for comfortable viewing in the day-light. Driving sunglasses with copper driver lenses relax the eye muscles to reduce stress and are designed to highlight the critical driving colours, i.e. red, amber and green. Due to the light levels within a car, these are usually UV filter category 2 lenses which transmit between 18% and 43% of light. For night driving, glasses must have transmittance properties in excess of 75% to be legal and so must be rated no more than UV filter category 0, many yellow lenses meet this criteria but it is important to check.
Most medical professionals would recommend a grey smoke tinted lens for everyday use as they have the benefits of increased light blocking, they do not distort colours and help to reduce glare. It is worth remembering that this guide is very much for general use and that speaking to a retailer or resource on tinted lenses is advised to find out which lens tint and colour will perform best for your chosen activity.
The lens material is just as important and will most often be glass, polycarbonate or acrylic. Each of these has various advantages for different uses. For example for outdoor sports or motorcycling use then a shatterproof polycarbonate lens will provide the best physical protection, polycarbonate is also very lightweight. Glass lenses do not flex or compress and do not expand or contract in heat or cold in a significant way meaning they will remain optically correct. Glass is the hardest and the most scratch-resistant material making it the longest-lasting but its impact resistance is poor and it is the heaviest. Acrylic lenses fall somewhere in between the two giving the best balance of optical performance and strength. These days the vast majority of sunglasses use a plastic material in their lenses due to their increased durability and light weight.