Sunglasses offer the following benefits.

• Sunglasses provide protection from ultraviolet rays in sunlight.
  Ultraviolet (UV) light damages the cornea and the retina. Good sunglasses can eliminate UV rays completely.
• Sunglasses provide protection from intense light.
  When the eye receives too much light, it naturally closes the iris. Once it has closed the iris as far as it can, the next step is squinting. If there is still too much light, as there can be when sunlight is reflecting off of snow, the result is damage to the retina. Good sunglasses can block light entering the eyes by as much as 97 percent.
• Sunglasses provide protection from glare.
  Certain surfaces, such as water, can reflect a great deal of light, and the bright spots can be distracting or can hide objects. Good sunglasses can completely eliminate this kind of glare using polarization.
• Sunglasses eliminate specific frequencies of light.
  Certain frequencies of light can blur vision, and others can enhance contrast. Choosing the right color for your sunglasses lets them work better in specific situations.

When you buy a pair of cheap sunglasses, you often give up all of these benefits and can even make things worse. For example, if your sunglasses offer no UV protection, you increase your exposure to UV rays. The cheap sunglasses block some of the light, causing your iris to open to allow more light in. This lets in more of the UV light as well, increasing the damage UV light can cause to the retina.

Buying the right pair of good sunglasses for the conditions in which you use them gives you maximum protection and performance. Click here to see how to choose a perfect pair of sunlgasses.