People often look for different qualities in sunglasses such as purpose, comfort, optical quality, UV protection, weight, warranty, price and brand.
For example, outdoor sportsmen often wear nylon frame sunglasses (flexible frames that don’t snap easily when pressure is applied). There are plenty of sunglasses in various shapes, sizes and colours if you are looking for fashion. If you want sunglasses for sunbathing or hiding your identity, you should go for wide frame sunglasses.
Can you elaborate on comfort?
Think of your clothes. If they are too large and baggy or too small and short, you’ll end up fidgeting with it. It’s the same story with sunglasses. You want a pair that fit well on your head. The nose bridge is also important as they help relieve pressure on your nose and cheeks. The height of the nose bridge is dependent on the size of your nose. Bigger noses need lower bridges, smaller noses need high bridges.
What do you mean by optical quality?
The clarity of vision, contrast and colour distortion of sunglasses. There are many coloured lenses with differing intensities. Grey and green lenses are neutral lenses with no colour distortion. Turquoise lenses increase contrast enhancement without colour distortion. Brown, yellow and orange lenses increase contrast enhancement but have some colour distortion. Blue and purple lenses are for fashion purposes. As for colour intensities, the darker the lens, the less light will pass through. Last of all, glass lenses offer better visual clarity compared with plastic.
What should I know about UV protection?
Not all sunglasses offer the same amount of UV protection. The European Union require sunglasses to have 95% UV protection (this means reflect or block 95% of the harmful UV rays emitted from the sun). Most opticians would recommend 99-100% (also known as UV400). There is no relation between the price of sunglasses and the amount of UV protection. The best sunglasses for UV protection are wide frame sunglasses with lenses that cover the whole of the eye area. A lot of designer brands are UV400 and have these large round frames for sale.
How about the weight of sunglasses?
The weight of the sunglasses depends on the frame and lens. Frames made of metal are heavier than plastic or nylon but there are lightweight titanium metal frames. For lenses, glass lenses are heavier than plastic. Heavy sunglasses will often leave indentation marks on the face upon removal.
What’s the difference between glass and plastic lenses?
The only advantage glass lenses have over plastic lenses is the better clarity of vision. Plastic lenses are lighter than glass, will not smash apart as easily and can be made much thinner.
Anything else you think I should know?
These are probably useless facts to you and me, but it makes an interesting read. Most people admit the look of the sunglasses is the biggest factor when deciding which one to buy. Some people wear sunglasses indoors not because they want the attention but rather, they just don’t want to make eye contact during a conversation. The biggest problem associated with sunglasses is misplacing them and forgetting where they’ve been laid. This is especially common on holiday, so take care when you have a good pair of designer sunglasses. You don't want to lose them!