When Exactly Should I Be Wearing Sunglasses?

Sunglasses play an important role in protecting your eyes from potentially harmful UV rays. This invisible form of energy takes the form of radiation which can damage your eyes if they are overexposed. But the pertinent question is, when exactly should I be wearing sunglasses?

One of the major determinants about deciding whether a particular situation calls for the use of sunglasses is the environment in which you are in. Rather surprisingly, UV exposure is greater on the snow, as well as on sand, pavement and water, than in more green environments. We often imagine a park at high noon to be some of the most dangerous conditions for UV exposure. But in fact, environments in which your surroundings are reflective, such as snow and water, provide some of the most perilous situations. This is because in such situations, the amount of UV is not easily absorbed by the greenery around you, but it hits the ground and is reflected back up towards your eyes. This means that you have UV light approaching your eyes both from above and from below.

UV rays are filtered out in the atmosphere. This essentially means that the gasses between you and the sun which are trapped within the earths gravitational pull filter out ultraviolet light before it reaches your eyes. In high altitudes, however, the concentration of those filtering gases, as well as their thickness, is significantly reduced. As a result, light rays are significantly stronger, and thus the presence of UV is much greater at higher altitudes.

Time of day is also one of the greatest determinants of UV risk. UV rays are directed from the sun. As a result, it should seem obvious that the risk of UV exposure is greatest when the sun is strongest, during the hours between 10 a.m. and 4 p.m.

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