Sunglasses have become a highly sought after and noticeable accessory, making a fashion statement in almost every walk of life. But, let us not forget that the primary purpose of wearing sunglasses is to protect the delicate tissues of the eyes from the harmful rays of the sun. While the sun is a source of light and warmth, and supports life on our planet, we need to be aware that its rays can be damaging.

The sun’s primary danger is in the form of ultraviolet (UV) radiation. There are three types of ultraviolet radiation. UV-C is absorbed by the ozone layer and whilst the ozone layer remains intact, does not pose a threat to us. Both UV-B and UV-A can have long-term damaging effects on the skin and the eyes. Even on a cloudy day, there is a danger of UV exposure. UV radiation can also be given off artificially, for example by welding machines and tanning beds.

Exposure to small amounts of UV radiation over a period of many years increases the risk of developing cataracts and may cause damage to the retina. The longer the eyes are exposed to UV radiation, the greater the risk of these visual conditions developing later in life. Since it is not clear how much exposure will cause damage, it is recommended that whenever we spend time outdoors we should wear a good pair of sunglasses as well as a cap or hat.

What is a GOOD pair of sunglasses?

Expensive sometimes means better, but not always; of course, top priority is UV protection; the glasses should block out 100% of both UV-A and UV-B radiation.

Size matters – larger lenses block out more UV rays than smaller ones, and wrap-around frames offer even better protection by blocking out some of the peripheral rays of the sun.

Lens colour – the colour of the lens is not directly related to its level of UV protection, and dark lenses can still allow UV rays to penetrate. The main consideration is the amount of UV radiation penetrating the lenses.

Driving - because the light varies while driving, choose lenses that offer glare protection and ability to see colours clearly. The windscreen of the car reduces the amount of UV radiation to a certain extent, but not enough to fully protect the eyes.

Polarizing lenses – these lenses help to block reflected light, for example on wet surfaces, reducing glare and increasing clarity, particularly in hazy conditions.

Anti-reflective coating – when this coating is applied to the back surface of a lens, it prevents reflections that can interfere with vision and reduces reflected UV rays.

Mirror coating – this coating decreases the amount of light and UV radiation passing through the lens.

Photochromic lenses—almost colourless in dim light and dark in sunlight, photochromic lenses are usually good at absorbing UV light.

Contact lenses – some contact lenses include UV protection, but this usually is not enough to filter out UV rays sufficiently, and added protection (sunglasses) should be worn.

Sunglasses for CHILDREN

The Skin Cancer Foundation reports that up to 25 percent of our lifetime exposure to UV radiation is sustained by the time a child turns 12 years of age. This is because children tend to spend more time outdoors and their eyes are more delicate than adults. From birth, protect a baby's eyes with a sunhat, umbrella or just by sitting them in the shade. As soon as possible, they should be wearing specially-designed sunglasses made with tough polycarbonate lenses that will not damage their eyes if they break.

Your optometrist will be able to advise you on the most effective protection against harmful UV radiation.