By Priya Suri

When choosing a pair of sunglasses, most of us focus on how we will look in them rather than the sun protection they should provide.

But if you want to protect your eyes from sun damage, there are several factors you should consider, said Dr Stan Isaacs, president of the Singapore Contact Lens Society and an optometrist who runs a private clinic at Camden Medical Centre.

UV Protection

Protection from ultraviolet (UV) light is essential for healthy eyes. Dr Isaacs said, "You should only choose sunglasses that offer over 90 per cent UV protection."

Reputable shops often display labels that state "UV400", meaning their glasses provide 100 per cent UV protection.

But if you already own a pair and don't know how they match up, visit an eye-care professional who will test your shades using a UV transmission meter.

And what about that commonly held myth that UV protection is needed when you're working in front of computer screens?

Dr Isaacs said, "Unless your computer is more than 15 years old, you don't need to worry about that. That's because there were no world standards for safety at the time. Nowadays, every screen has to meet radiation emission standards."

Tint

UV coatings are usually colourless. Treated clear lenses, with no colour-tint, can still be UV-light blockers. Different tints work better in different environments and the colour you choose is a matter of personal taste.

Dr Isaacs said: "Most people would require gray, brown or blue lenses for normal, everyday use. These colours reduce glare without distorting colours too much."

Price

Even sunglasses from designer brands may not offer 100 per cent UV protection.

Dr Isaacs recommends buying sunglasses of reputable brands that are manufactured in Europe, the United States and Australia as these countries have strict safety standards.

And don't believe everything you read: just because glasses have a sticker claiming UV protection doesn't mean it's true.

Frames

Styles that wrap all the way round the temples are best at preventing eye strain as they don't let light enter from the sides.

It's also important to choose frames that allow the lenses to be comfortably positioned in front of the eyes.

Polarising Lenses

Polarised filters help to reduce the glare from reflective surfaces such as water, snow and roads, so your vision is not compromised in strong light.

They are perfectly suited for individuals who enjoy fishing, skiing and sailing.

Children

Children need sun protection too.

Don't let your child wear toy glasses when he's playing out in the sun.

Instead, buy him shatter-proof polycarbonate glasses that give the same UV protection as adult glasses.

This article was first published in Mind Your Body, The Straits Times on June 25, 2008.