Our optometrist talks about sunglasses - what should you know?

Our in-house optometrist sat down with us to go over some facts about sunglasses. When it comes to sunglasses, people don’t always know all there is to know. We are all aware that we should protect our eyes from harsh sunlight. A good pair of sunnies will usually do the trick, right? But what makes a pair of sunglasses good enough? We asked our optometrist Kristýna a few of the most common questions. Her answers should help you understand your sunglasses better, and give you an idea of how to pick the right pair. So, let’s hear what a professional has to say about this topic.

Our Alensa optometrist Kristýna Štěbetáková

How can we determine the quality of a pair of sunglasses?

It’s possible to estimate the quality of sunglasses based on the lens colour -- though that alone isn’t always the most accurate indicator. Sunglasses with lightly coloured lenses can still be good, but usually offer less protection than darker lenses. You could say that lightly tinted sunglasses are more of an urban fashion thing, and darker ones are generally better for protection.

The real indicator for quality is knowing the specifics of a certain pair of sunglasses. Each pair is usually marked with a label or inscription on the side or on the lens itself. This label should clearly show if the glasses are polarized, which category of protection the glasses offer, CE certificate info, or if they use PRIZM technology*, for example. If sunglasses are unmarked, you can never be sure if their quality is sufficient. In case you can’t find any markings or labels, the seller should be able to provide all necessary specifics.

*PRIZM is a newly developed technology by Oakley that enhances colour and contrast perception.

Why is it essential to pick the right sunnies? Which category do we need?

Sunglasses are first and foremost a way to protect the retina from harmful UV rays. Of course, they also prevent us from getting blinded by harsh light. A category indicates how much light a lens lets through and, in other words, how dark a lens is. We can generally consider 4 categories: 0–1, 2, 3, 4. Category 0-1 lenses are clear or have a very light tint. These lenses are common for clear protective eyewear or for cosmetic eyewear. Category 2 is the most commonly sold and worn. Category 2 lenses are tinted up to 70%. Category 3 lenses are about 85% tinted. This makes them slightly darker and better suited for harsh sunlight. These are your go-to for very sunny days. Category 4 lenses are about 95% tinted. These sunglasses truly block a lot of light and provide a high degree of protection. They are most suited for the mountains, the beach, or a desert area. They are intended for specific uses and extremely sunny conditions only. You should never wear category 4 sunglasses while driving.

Can you tell us more about the UV filter?

UV protection should work against both UVA and UVB radiation. A UV filter is not the same as lens colour. For example, some clear lenses can protect against UVA. Even a blue light-blocking filter absorbs some UV rays. However, if the lens is tinted, it usually achieves better protection against both UVA and UVB. Proper UV protection is indicated via a CE certificate. This makes it easy for you to spot sunglasses that have a quality UV filter. Or, you can look for a UV 400 label. UVB has a wavelength of 280–315 nanometres and UVA has one of 315–380 nanometres. So, total protection is achieved by blocking up to 380 nm. UV 400 blocks, well... up to 400 nanometres and provides optimal protection.

What is this CE certificate?

The European CE certificate guarantees UV protection up to 380 nanometres. In other words, this means that your sunglasses meet the European Union safety and protection standard. The CE mark can be found on the inside of the temples. It should also be accompanied by additional info such as polarization, category info, PRIZM Technology, etc. As I mentioned before, sunglasses specifics and labels will show you what you need to know. So, when in doubt, look for the CE marking!

CE certificate on sunglasses

Which sunglasses are recommended for children and which for adults?

For your kids, the most important thing is to properly protect their eyes. Since they’re still growing and developing, you should get them darker quality sunglasses. For adults, it depends on how you want to use them. If you want to wear them in the city or during spring, a lower level of UV protection is more than enough and you can opt for lighter sunglasses. During summer, or while out on a beach or in the mountains, a higher degree of UV protection is necessary. If you’re in an environment that has a lot of reflected light, such as while driving or while out on the water, you can even get yourself a pair of polarized sunglasses. This will help stop those blinding surface reflections.

Can we do anything else to protect our eyes during spring and summer?

Sunglasses are a necessity when talking about protection against sunlight, of course. If you wear contact lenses, you can further protect your eyes with lenses that have a built-in UV filter. Or, if you wear glasses, you can try photochromic transition eyeglass lenses. That way, you can have clear glasses indoors and darker lenses while outside. And since glasses and sunglasses don’t cover the sides of the face, wearing a hat or cap also helps. Lastly, you can carry around some moisturising eye drops for when your eyes dry out or become irritated.