Sunglasses have become as ubiquitous as sun sand and sea in Australia. Many of us won't even venture into the sunlight without them and
Why Aussies need sunnies
If you return from Europe, where the sky is hazier and less blue, and step into the Australian sun, your eyes will notice the difference. There are a few reasons for this. The earth is closer to the sun in January (Southern Hemisphere summer) than in July (Northern Hemisphere summer) and the air is generally clearer here. These result in a UV dose that is 15 per cent higher for the same latitude than in the Northern Hemisphere.
Also, between 1979 and 1992 the ozone depleted and cloud cover over northern Australia decreased, resulting in a four per cent rise in UV dose in Australia\'s north. This is not helped by the fact that many Australians live an outdoor lifestyle.
Things you need to know when buying sunglasses
- Make sure you buy glasses that have a sticker saying they conform to Australian standards.
- To check for imperfections in the lenses, hold the glasses at arm's length, then look through them at a straight line in the distance, such as the edge of a door. Slowly move the lens across the line. If the straight edge distorts, sways, curves or moves, the lens is flawed.
- Polarised lenses cut reflected glare - when sunlight bounces off smooth surfaces such as a pavement or the water. These can be especially helpful when driving, at the beach or in the snow.
- If you're using your sunglasses for water or snow sports such as sailing or skiing, look for double-gradient lenses (dark on the top and bottom and lighter in the middle), as light reflects up off the water or snow.
Save your eyesight
Repeated exposure to UV radiation causes short-term eye complaints, including excessive blinking, swelling or difficulty looking at strong light, and more serious damage such as cataracts, pterygiums (overgrowth of tissue from the white of the eye onto the cornea), solar keratopathy (cloudiness of the cornea), cancer of the conjunctiva and skin cancer of the eyelids. Around 160,000 cataracts are treated in Australia each year. It is estimated almost half of the 8600 cases of pterygium treated annually in Australia are also caused by sun exposure.
Q Should kids wear sunnies too?
Q Should kids wear sunnies too?
A Yes. Eye damage from UV radiation is cumulative, so it is important to protect children's eyes, says Professor Dain. As UV exposure in childhood is related to skin problems later in life, it's probably much the same for eyes. "With very young children there are reasons to use good optical-quality lenses, but avoid dark tints."