Showing posts with label UV. Show all posts
Showing posts with label UV. Show all posts

Friday, July 18, 2014

Tints, mirrors, polarization and other sunwear technology



We've all become much more aware of the need to protect ourselves from the damage that the sun's UV rays can cause.  Powerful campaigns like Slip-Slap-Slop has helped to educate us to the need to make sure we take the necessary precautions.  The importance of the advice from these campaigns can not be ignored and another factor which they help raise is the need to protect our eyes as well.  When it comes to choosing sunglasses, though, the choices can seem a little bewildering.

Nikon's SunStyle lens selections
Standard tinted lenses work by absorbing a portion of the visible light going through a lens, the light allowed to pass through is what gives the colour of the tint we see.  When choosing a tint colour, there is not really a "correct" choice, it all comes down to personal preference and taking in to account when you will be wearing the glasses.

A few things to consider are that a very dark tint will be better for brighter conditions.  Coloured tints like brown, green and blue will alter the apparent colour of objects that you see, grey should not.  The darkness of the tint does not indicate the level of UV protection.

ic! berlin Boombox Noize
Slightly different from absorption tints, are mirror tints.  These tints reflect the light, rather than absorb it, and work by having a thin layer of a metal on the front surface of the lens, often combined with a standard absorption tint within the lens.  Again it is important to check for the UV protection as the reflective surface alone does not guarantee UV protection.

There are many options when it comes to mirror coatings and they can produce dramatically varying effects, dependent on the metals used and the thickness of the coatings. Sports eyewear often includes a subtle flash coating of just a minimal amount of reflectance, fashion ranges include fantastic colours to completement the frames.  Perhaps the current masters of this are ic berlin!

Another common consideration when it comes to sunglass lenses is decide if you would benefit from polarized lenses.  Polarized lenses work like standard sunglass tints, however, have a special filter in them to also remove light which is poloarized.  Sources of polarized light tend to be surfaces which reflect light, like water, snow.

Many outdoor enthusiasts enjoy the benefit of polarized lenses to help reduce distracting glare and have enhanced vision for their hobbies, however, polarized lenses are not always the best option.  Polarized lenses can create issues when trying to read the surface, for example in downhill skiing or golf.  They can also block out light from LED and LCD screens, making smartphones, tablets and even dashboard dials difficult to read.

One newer development with polarized lenses is a trend for lenses which also provide true or even enhanced colour perception.  Examples of this include the Nikon Radiance lens and the Smith Optics Chromapop lens:  

Smith Optics Chromapop
The choice between the different options can seem bewildering and it may not be easy to work out what is the best option for you.  Our best advice is to come in to Ocean and spends some time chatting with us about what you want and how you're going to use your glasses and we'll help guide you through the choices.  Then get outdoors and enjoy the summer!





Wednesday, March 5, 2014

UV protection and You!

We are all much better now at using sunscreen to protect ourselves from the damage that can happen through UV rays.  Can the same be said about protecting our eyes?

The harmful effects of ultra-violet radiation on the eyes has now been well documented, however, what many do not appreciate is how important it is to protect children's eyes.  Children spend more time playing outside, their pupils are larger allowing for more light (including non-visible light) to enter the eyes.  Research has also shown that a significant amount of our total lifetime UV exposure now happens by the age of 18 and we know that the damage adds up over time.

So how can we protect our eyes?

UV protection -definitely cool
There's obvious steps which can be taken, common with general sun protection, like wearing a wide brimmed hat.  We can not, however, put sun cream in our eyes, so how do we ensure that they are fully protected?

Sunglasses

The most obvious choice would be to use sunglasses, as long as they have UV protection.  You can look for certain marks like UVX or UV400 to ensure that the sunglasses will do the job properly.  Without proper UV protection, sunglasses could actually make sun damage worse as the pupils will dilate behind the dark lenses allowing more UV to enter they eye than without.

Sunglasses should be well fitting and thankfully current trends of either wrapped style or over-sized sunglasses definitely help to max out the protection and reduce peripheral light from entering the eyes.

Prescription Glasses

It may not be obvious that your prescription glasses can actually help to reduce the amount of UV light getting to the eyes.  Higher index plastic lens materials have inherent in-built UV protection as part of their optical characteristics and even standard plastic (1.5 index) can have a UV blocking treatment applied to it. 

With added benefits of being robust and durable, it is easily argued that 1.6 index plastic should now be our standard lens material of choice.  It is thinner and lighter than standard plastic, safer for the eyes with the UV protection and particularly beneficial in children's glasses as it is incredibly tough.

While prescription glasses wouldn't replace good sunglasses for overall sun protection, it is worthwhile taking the time to discuss your requirements with your optician to make sure that you are making the best choice overall.

Contact Lenses

We are increasingly finding contact lenses coming with built in UV protection and it is a feature of the lenses manufactured by Acuvue that all of their lenses have a UV blocker.  The big advantage of contact lenses in UV protection is in reducing peripheral light which gets in to the eye from oblique angles, light coming from the sides, above or below.  This Peripheral Light Factor can cause real problems for glasses and sunglasses as the light can "creep" around the edges of the glasses or be reflected from the skin and then from the back surface of the lens.

Acuvue lenses with UV protection as standard
While contact lenses will not protect the whole eye, as they only cover the cornea in the center, they will add a level of protection which is a great supplement to good quality sunglasses.  They will also allow you to choose from non-prescription sunglasses, perhaps opening up options in style, selection and having multiple pairs to suit your mood or the environment.

Whatever you are doing, whatever time of year, when you are going outside make sure that you have the best protection available and if you are unsure of what works for you, speak to your optician or optometrist for the best advice.