A pair of sunglasses seems so simple-but what a difference they make to your look and safe enjoyment of a sunny day. As well as being trendy, a pair of dark glasses is a sophisticated piece of kit. There’s a bewildering array of choice out there. For example, there are differences between tinted, reflective, photochromic (lenses that darken on exposure to ultraviolet or UV light), and polarising sunglasses which eliminate glare. The style of the frame and size of the lenses also make a difference. Essentially there are four things that a good pair of sunglasses should do for you: Sunglasses provide protection from ultraviolet rays in sunlight. UV light damages the cornea and the retina. There are two types of UV that can cause damage to the eye: UVB and UVA. UVA penetrates more deeply. Sunglasses can block up to 97 per cent of intense light. When the eye receives too much light, it naturally closes the iris and then squints. If there is too much light, as there can be when sun shines off snow, the retina can be damaged. Polarised sunglasses provide protection from glare. Certain surfaces, such as water, can reflect a great deal of light, and the bright spots can be distracting or can hide objects. Sunglasses eliminate specific frequencies of light that can blur vision, and others can enhance contrast. Choosing the right colour for your sunglasses lets them work better in specific situations. To gain maximum protection and performance, it’s important to buy the right pair of quality sunglasses for the conditions in which you intend to use them. Investing in cheap cosmetic sunglasses is a false economy. For example, if your sunglasses offer no UV protection, you increase your exposure to UV rays. The cheap sunglasses block some of the light, causing your iris to open to allow more light in. This lets in more of the UV light as well, increasing the damage UV light can cause to the retina. While the tint colour and a similar frame design may make them look like Dior or D&G, the actual lenses are very different. Inexpensive sunglasses have lenses made of ordinary plastic with a thin coating on them. Spex have one of the largest collections of Designer branded sunglasses in the North West, usually at Discounted prices.