There are three features to look out for in sunglass lenses:
- UV Protected
- Polarized or Non-polarized
What are UV protected Lenses?
UV protected lenses have a special coating over it that prevents and resists the harmful UV rays emitted from the sun to directly come in contact with the wearer’s eye, eventually protecting the wearer from serious eye damage.
Why choose UV protected lenses?
UV abbreviated from Ultra Violet rays which are emitted by the sun are considered to be one of the most dangerous and harmful elements for the skin when stepping outside. The same amount of harm and danger can be caused to the eyes by these UV rays. That is why the most basic feature of a sunglass should be to protect the wearer from this harm or danger and also reflect/divert the glare which shines directly into the eyes. UV protected lenses shield the wearer's eyes from these harmful UVA and UVB rays, thus preventing serious eye damage.
How do you identify if your lenses are UV protected or not?
To identify whether the sunglasses are UV protected or not simply ask the eye professionals at the store to check the effectiveness of the sun wear against the UV rays using an instrument called Photometer. Though the easiest way is to check the details on the products itself as almost every product has this detail printed on it, provided it is UV protected. All known, branded products and those dispensed by us are by default fitted with UV protected lenses.
What are Polarized lenses?
In scientific terms Polarization (also polarisation) is a property applied to transverse waves that specifies the geometrical orientation of the oscillations. No need to check your 7th grade science textbooks again, in simple words Polarization is the process of dividing a single light ray into multiple pieces and eventually making its effect null on any surface.
The same phenomenon occurs when a polarised coating is applied on the sunglass lenses or built into it. The direct sharp sun rays coming on the eyes of the wearer are resisted by the polarised coating. This eventually improves the sight and prevents the sudden distraction caused by the flare. Polarized lenses are very helpful and it is majorly used in sporting activities and events
How do you identify if your lenses are Polarised or not?
The best way to check if a lens is polarized or not is to hold the lens in front of a suitable screen (available at all authorised optical outlets) and see if the colours pop or not. If the colour changes it's a polarized lens else its not.
Non-Polarized lenses have no effect on the incoming glare i.e. they are the opposite of Polarized lenses. Using such lenses does not cut glare, making it difficult to see but not making it harmful either if the lenses are UV protected.
What are Photochromic Lenses?
Theses are lenses which tend to get darker when exposed to bright sunlight and are known as photochromic lenses. Sunglasses lenses are coated or inbuilt with a photochromic layer to reduce or dismiss the harsh effect of bright sunlight by adapting the lens colour depending on the intensity of light from the sun; ultimately easing the effect on the eyes of the wearer.
The big advantage of photochromic lenses is that they adapt to bright sunlight within the blink of an eye.