onflicting Claims

Manufacturers have developed new sunglasses designed to protect eyes from the sun's
harmful effects. They promise protection from ultraviolet light and other kinds of natural
radiation. It is more important to protect your eyes from some kinds of light than others.

"Blocks 99% of ultraviolet rays"
You should always buy sunglasses with this feature. Long-term exposure to ultraviolet
(UV) radiation in sunlight is linked to eye disease. Both plastic and glass lenses absorb
some UV light, but UV absorption can be improved by adding chemicals to the lens
material during manufacturing or by applying special lens coatings. Shop for sunglasses
that block 99 or 100% of all UV light. Some manufacturers' labels say "UV absorption up
to 400nm." This is the same thing as 100% UV absorption.

"Blocks 90% of infrared rays"
Infrared wavelengths are invisible (they are longer than light rays that you can see) and
produce heat. Sunlight has low levels of infrared rays, and the eye tolerates infrared well.
Some sunglasses manufacturers make health claims for their products based on infrared
protection, but research has not shown a close connection between eye disease and
infrared rays.