We are all aware of the harmful effects of the sun on our skin but UVA and UVB radiation is just as damaging to our eyes. The World Health Organisation recommends wearing a good pair of sunglasses, even on a cloudy day, to protect eyes from the ultraviolet radiation that you cannot see or feel. In Australia they talk about slip, slop, slap, wrap. Slip on a top, slap on a cap, slop on some sun cream and the ‘wrap’ stands for wrapped sunglasses! Put them on, your eyes are so important, our senses are the wonderous things which connect us to the world.
Bigatmo sunglasses filter out 100% of harmful UVA and UVB rays. This is important because today more UV rays are reaching the earth because of the reduction in the ozone layer. Everyone needs the right sun protection for their eyes and this becomes even more important for sports enthusiasts, pilots and those who spend time outdoors in high risk environments such as snow and water. A grassy or watery surface reflects up to 10% of the sun’s rays, but a snow-covered surface can reflect at least 80%. The intensity of UV rays also increases with altitude, because the reduction in absorption factors is inversely proportional. It is estimated that the intensity of the sun’s rays increases by between 6% and 8% every 1,000 meters, and at very high altitudes reaches 12% every 1,000 meters.
There are three types of UV radiation:
- UVA – These are low energy rays that cause ageing, they are deeply penetrating and not blocked by the ozone layer.
- UVB – These are more powerful rays with the energy to burn. They are partially absorbed by the ozone layer but as this is reduced they become more damaging.
- UVC – These are the most damaging rays but they are completely absorbed by the ozone layer and do not reach the earth’s surface.
- Wear sunglasses with high quality lenses to protect eye health.
- If they don’t bear CE markings, don’t buy them.
- Very dark lenses can prevent the pupil constricting. The pupil may dilate and therefore let more harmful UV rays into the eye when the sunglasses are not UV protective.
- Sunglasses should block out 75 – 90% of visible light and 99 – 100% of UVA and UVB rays.
- Wrap around sunglasses help prevent light and UV from getting behind the lenses and in to your eyes.
- High impact resistant lenses are obviously much safer.
- Light coloured eyes (blue, grey or green) need more protection.
Studies show that exposure to UVA & UVB radiation can contribute to the risk of the following eye disorders:
- Pterygium – A benign growth on the eye surface.
- Macular Degeneration – Damage to the central vision area due to cumulative UV radiation.
- Cateracts – Responsible for one half of 35 million cases of blindness worldwide. It is a cloudiness of the eye lens caused by long term over exposure to UV radiation.
In addition there are other disorders which are also associated with UV exposure:
- Dry eye syndrome – The heat and the sun can both cause dryness in the eye: they evaporate the lachrymal film, the protective veil that covers the cornea and provides a natural form of protection for the eye.
- Keratitis – Symptoms include intense pain and difficulty in opening the eyes. Fixed, prolonged exposure to the sun (for instance sunbathing) heats up and completely dries the eye and causes serious problems to the epithelial cells.
- Conjunctivitis – Puffy, red eyes that burn and itch are the signs of conjunctivitis, which can also be caused by exposure to strong winds.