Sunglasses and Ultraviolet (UV) Protection

Most people will agree that of all our senses our eyes are what we cherish the most, yet we are possibly exposing them to danger on a regular basis by simply going outside.

Research has shown that over time the suns rays can cause serious damage to the eyes and the surrounding skin. This can sometimes lead to vision loss and contribute to the formation of ocular conditions such as cataracts, macular degeneration, pterygium, snow blindness and eyelid cancers.

The good news is, by wearing a good quality pair of sunglasses, ideally starting from the earliest age possible one can help to keep our eyes healthy.

To the eye, Ultra-Violet radiation is a dangerous component inflicting cumulative damage. UV radiation can be divided into 3 categories, each having different effects upon the eye; UVC, UVB, and UVA.

UV-C radiation originates from the solar system and is readily absorbed in the earth's atmosphere by the ozone layer and does not present any threat.  Note this is in contrast to man made sources of UV-C such as electric welding arcs which can be harmful to the eyes if proper protection is not worn.

Ultraviolet A (UVA) and Ultraviolet B (UVB)  are powerful invisible rays with wavelengths shorter than visible light,  and are considered to be the most dangerous part of sunlight.
These can cause cataracts, eyelid cancers and other skin cancers, and are considered to play a part in macular degeneration, which is a major cause of vision loss for people over the age of 60.  In addition, UV rays can prematurely wrinkle and age the skin around the eyes.

Visible Light/Blue Light  
High energy blue light in the violet/blue spectrum is a potential contributor to cataracts and other serious eye conditions.

While the cornea and crystalline lens absorbs some of the ultraviolet rays, high percentages of blue light can still pass through causing cumulative damage to the retina and skin cells overtime.

Are you at RISK???

While everyone is at risk of the harmful effects of UVA and UVB radiation, certain people and scenarios, result in increased exposure to the Suns radiation and therefore greater risk.

  • Infants and children - In the first decade of life the lens of the eye is most transparent and may represent the period of greatest exposure, even though the effects of sun damage may not become apparent until much later in life.  UV damage is cumulative and it is estimated that 50 to 80% of the lifetime exposure to ultraviolet occurs by the age of 18 years. This means, that the longer your eyes are exposed to UV radiation the greater the risk of developing conditions such as cataracts later on in life.
  • Fair Skin - the fairer your skin, the greater your age and the lighter your eyes, the higher you're long term risk, particularly if your work or recreation involves prolonged sunlight exposure. Light eyes are at increased risk of certain eye diseases and skin cancers because they contain less of the protective pigment melanin.
  • Ordinary sunglasses, even the best  are not able to protect your eyes from certain intense  light sources such as Arc Welding, tanning lights, snowfields or gazing directly at the sun (especially during a solar eclipse). Without adequate protection, looking at any of these light sources can cause a painful corneal condition called photokeratitis, possible loss of central vision or permanent harm.
  • Medications - Certain medications such as psoriasis drugs, anti-histamines, oral contraceptives, tetracycline, allopurinol etc increase ones sensitivity to ultraviolet light.
  • One is at increased exposure to harmful UV radiation when one is around Water, snow and outdoor sports like skiing at high altitudes

What to look for when purchasing Sunglasses

  • Block out 99 to 100 percent of UV-A and UV-B radiation with wavelengths up to 400nm. Sunglasses which meet this requirement are often labeled as "UV400".
  • Screen out 75 to 90 percent of visible light.
  • Check that the sunglasses are marked with the CE mark for quality standards.
  • The lenses should be perfectly matched in colour and free of distortion and imperfections.
  • Wraparound glasses are shaped to keep light entering from around the frame and can often be combined with your prescription.
  • Polarized lenses cut down on reflected glare such as looking in water during fishing and water sports, and pavement/roads while driving. In addition they improve contrast, enhance colour perception and   provide greater visual comfort. They need to be (and usually are) combined with an additional chemical to block the harmful UV-A and UV-B rays.
  • Impact-resistant lenses are essential for a sporty or active lifestyle as they are made from polycarbonate or toughened glass
  • Wearing a hat or cap with a wide brim will provide additional protection to your eyes and the surrounding orbit.

Please note at Barnard Levit Optometrists, there is always a fully qualified Dispensing Optician available to advise you on the most suitable sunglasses and provide information on sport specific tints and frames.