American National Standards Institute (ANSI) Safety standards for eyewear consists of the following features:

• They go through basic impact tests where each lens is test on its own. For the higher impact class, the frame and lenses are together as one.
• Non-prescription lenses are considered to be structurally weaker than prescription lenses when being used for high impact; this is do to the prescription lenses being thicker.
• Safety lenses now have 2 classifications: basic and high impact
• The “Drop Ball” test, which will prove whether the basic impact is passed or failed. This test consists of a steel ball, one-inch in diameter being dropped onto the lens from 50 inches high. In order to pass the test the lens must not crack, chip or break. All safety lenses must go through this test. When using plastic lenses, only a sample of a rather large batch must undergo testing, not every pair of lenses.
• Another high impact test is one where a steel ball, a quarter inch in diameter is launched at the lens at a speed of 150 feet per second. In order to pass the lens must no chip, crack, break and cannot come undone or dislodge from the lens holder.

To determine if a safety goggle or glasses lens have passed the high speed test as described above, you will see a “+” marking, which confirms the lens success for high velocity impact.  You should also look for these markings, “V” and “S”. The “V” indicates that the lens is photochromic. The “S” indicates that the lens has a special tint. In some cases (depending on use or job) some glasses or goggles may require or come with a mild to moderate tint. For example a person or job that requires you to cut or weld might require a thicker lens and a stronger tint.