Medical Questions » Eyes Questions » Question No. 345
| Question: | What are the best sunglasses to buy? |
| Answer: | There are a very wide range of sunglasses on the market, but very few manufacturers give any information about the characteristics of the lenses, and most people buy for appearance rather than effectiveness.
A good pair of sunglasses should be large enough to prevent glare from entering the eye from around the edges. They should absorb all the ultraviolet (UV) and infra-red radiation frequencies, as these are totally unnecessary for vision, but may be harmful to the eye itself.
The total light transmission of the sunglass lenses should be reduced to below 40%, but some go as low as 15%. Polatised lenses, which reduce reflected glare markedly, are also better than non-polarised ones. The actual colour of the lens makes little difference, but the variable shaded lenses are better avoided, as they do not give adequate protection from reflected glare.
Excess sun on the eyes will aggravate cataracts, and can cause an overgrowth of tissue on the white of the eye called a pterygium. It is just as sensible to protect your eyes with good sunglasses as it is to protect your skin with a good sun screen lotion.
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