What is the difference between POLARISED SUNGLASSES and UV 400 SUNGLASSES?

Why should we wear sunglasses ? 

What are UV rays? Ultraviolet radiation is a type of light that is not visible to the human eye, and is  part of the rays that reach us from the sun. 

Excessive exposure to UV Rays can result in the front surface of the eye becoming damaged, much like sunburn on the skin. Without proper precautions, these rays can also have harmful cumulative effects that may develop over time.

Too much exposure to UV rays may result in one or more of the following eye conditions;

  • Cataracts: The lens inside the eye can become clouded, seriously obstructing normal vision. 
  • Skin cancer around the eyelids: Skin cancer around the eye most commonly develops in the form of lesions around the lower eyelid, but it can also appear on the upper eyelid or the corner of the eye.
  • Pterygium: A non-cancerous growth may develop in the corner of the eye, possibly obstructing the cornea and obstructing vision.
  • Photokeratitis: Highly painful (but usually temporary) burn to the cornea. Most commonly associated with not wearing sunglasses.

Please see the websites below for more information on the effect of sun on your eyes;

www.eyesiteonwellness.com/the-sun-and-your-eyes-what-you-need-to-know/

www.healthywomen.org/content/article/protecting-your-eyes-sun-damage

UV Sunglasses

The standards in the European Union on UV sunglasses are very strict and insist that they block 99-100% of UV radiation.  Make sure that your sunglasses meet these standards by looking for the “CE” British and European standard markings on the label, or BS EN ISO 12312-1-2013. 

Another  consideration when buying sunglasses is the darkness of the lens. This actually has nothing to do with UV protection, but can help deal with varying levels of brightness.

There are four filter levels ranging from 1-4; 

  • Category 1 Light: Suitable for day driving and low sunlight
  • Category 2 Medium: Suitable for day driving use in medium sunlight
  • Category 3 Dark: Suitable for day driving use in bright sunlight
  • Category 4 Very Dark: Use in very bright conditions. NOT SUITABLE FOR DAY OR NIGHT DRIVING  

Lenses also come in different colours which can be useful in different conditions;

  • Yellow lenses: Useful in overcast or snowy conditions
  • Brown lenses: Good for outdoor activities
  • Grey lenses: Retain accurate colour perception, so are good for driving 

The other crucial thing to consider is the the style of sunglasses, researchers have found that this plays a bigger role in protecting your eyes than you might think.  Wraparound lenses that sit close to the face blocking the most UV rays offer the best protection. 

Polarised Sunglasses 

Polarised sunglasses, feature a special filter that is specifically designed to reduce glare from intense reflected light, which can interfere with vision. It does this by only allowing vertically reflected light through the lens while blocking horizontally reflected light. Light reflected from surfaces such as roads, sidewalks, and especially water, can cause problematic glare. 

It is reported that there are 3000 road accidents caused by the glare of the sun so wearing polarised sunglasses while driving could help prevent an accident. 

Polarised lenses can have advantages over traditional UV sunglasses by reducing glare in bright conditions, and this can be particularly important for people performing in sports – such as cycling – or taking part in water-based activities. People who engage in snow sports, where reflected glare can be almost blinding, almost exclusively use polarised lenses. 

 The reduction in glare offered by polarised sunglasses can have a number of positive effects. It not only provides protection from exposure to bright light, it can also enhance visibility, contrast, clarity and depth perception. The one disadvantage with polarised is that it is difficult to read an LCD or LED screen. If you require to use your phone, look at a screen frequently, look at aircraft controls Polarised will not be suitable. 

Polarised Sunglasses while they reduce glare, and reflection have some UV protection, but do not have the same 400UV protection as sunglasses unless SPECIFICALLY labelled with UV protection.

Polarised glasses are useful for driving and all outdoor activities, to reduce  glare and make objects clearer but remember, they are not suitable to read LCD or LED screens. For all other occassions when the sun is out a better level of protection from UV rays is offered wearing wraparound UV 400 sunglasses.

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