Do you wear sun protection for your eyes? This means restricting total visible light and reducing ultra violet.
One of the major causes of cataracts (fogging of the cornea) is exposure to solar ultra violet. This was discovered by studies of progressing blindness among fishermen. Light bouncing from the ocean surface increases the risk over that experienced by farmers and other outdoor workers. UV also contributes to macular degeneration in the eye.
Fortunately, sun glasses are now easy to find, cover a wide price range, and can offer both tinted and polarized filtering. If you don't need focus correction, sun "glasses" (can be plastic) can be very light weight.
By the way, the "photochromic" sun specs which darken under UV exposure aren't quite the miracle claimed by their makers. They range between not dark enough in the sun and too dark when they should be clear. They also do poorly behind automotive windshields and in cold weather. The delay in color change can be long enough for the user to have changed spectacles.
Polarizing filters can reduce light polarized in one angle of rotation, such as happens when sunlight is reflected from water, shiny metal, snow, and so forth. Reduction of this random glare is extremely helpful for focus. Competitors in fishing, boating, golf, skiing often rave about the benefits. Light reflected from mostly flat water is polarized horizontally, so the sunglasses are polarized vertically.
When the Polaroid Company began making its first product, polarized sunglasses, the plastic was fairly resistant to scratching from dust and handling. Most polarized clip-ons now seem to be quite scratchable, unless you seek out a really good brand. Regular prescription spectacles can have lenses of glass or poly carbonate plastic plus scratch resistant coating, and both these lens types can have polarized filtration.
If you wear contact lenses, it is very simple to place sun spectacles in front of them. Several companies are now offering contact lenses with UV filtration. The UV contacts also protect the cornea from light coming from the top and sides, which can bounce off the inside of glasses. However, the contacts cannot protect the whites, nor filter as strongly as spectacles, nor is it practical for contacts to be polarized. Be skeptical of contacts which claim to offer better UV protection than spectacles. The ultimate UV protection comes from combination of UV contacts and spectacles with UV coating.
Eye damage from ultra violet is cumulative over many years. Therefore, the benefits of particular spectacles or contacts will be difficult to judge outside of large statistical studies.
For more articles about safe and enjoyable use of contact lenses and spectacles, see http://3daycontacts.com/articlelist.htm.
© 2009 Dr. Don Miller
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