Technical information
on sunglasses filter categories.
There are 5 filter
classifications for sunglasses: 1, 2, 3, 4, 5
The number is an
indicator as to how much light passes through the lens.
Category 0 will allow
80 - 100%
Category 1 will allow 43 - 80%
Category 2 will allow 18 - 43%
Category 3 will allow 8 - 18%
Category 4 will allow 3 - 8%
Categories
0 and 1 are used mainly for fashion and do not significantly
reduce the glare from bright sunlight.
Category 2 is for
sunny weather and driving.
Category 3 is for
bright sunlight, driving and general purpose wear.
Category 4 is for very
bright conditions and should not be worn whilst driving or
operating machinery.