Safety glasses can provide several forms of protection. The safety standard that prescription safety glasses meet will determine the types of hazards against which eyewear protects your eyes and the degree of protection that glasses or goggles provide. Here are several types of protection you can obtain when you put on a pair of safety glasses.
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Impact-Rated Frames and Lenses
Safety glasses act as a protective layer that shields your eyes from impact. Regardless of whether frames are subjected to testing that meets requirements for the American National Standards Institute basic or high-mass and high-velocity impact testing or ballistic testing for U.S. Military standards, eyewear must stay in place and lenses must not shatter.
Basic ANSI Z87 testing involves dropping a steel ball that is one inch in diameter on eyewear from a height of 50 inches. High-mass testing involves dropping a nearly 18-ounce weight from a height of 50 inches onto safety glasses that are mounted on a head form. High-velocity testing involves shooting steel balls that are ¼-inch in diameter at 20 specified points of impact on eyewear. Military ballistic testing is approximately four times as intense as basic ANSI Z87 testing.
Prescription Safety Glasses Benefits
The frames of safety glasses are designed to stand up to impact and other eye safety hazards. It is important that any lenses that you have an optical service put in safety-rated frames are up to the same rigorous standards. Note that Plano and prescription safety lenses bear different markings, and look for the right markings on safety frames or prescription lenses.
A Z87 marking indicates that eyewear meets the basic ANSI impact standard, while Z87+ distinguishes eyewear with the ANSI high-mass and high-velocity impact rating. Prescription lenses have different markings, namely Z87-2 to indicate a basic impact rating and Z87-2+ for prescription lenses that have a high-mass and high-velocity impact resistance rating. Make sure that your safety frames and lenses keep your eyes protected in environments that pose eye safety risks.
Dust and Liquid Hazard Protection
Close-fitting eyewear with more complete coverage can provide more protection from dust, droplets, and splashes than standard safety glasses. Convertible glasses or goggles with facial cavity seals that are made of foam, rubber, thermoplastic, or other impermeable, soft, and flexible materials can help to protect your eyes from exposure to coarse and fine particles in addition to droplets and splashes of liquid.
Some styles of convertible spectacles come with removable facial seals, side shields, or head straps. This versatile eyewear may not provide the same level of protection as a pair of safety goggles, particularly if you are not using these features when an incident occurs.
You should wear prescription safety glasses or safety glasses with non-prescription lenses based on your vision needs and the hazards to which your eyes are exposed. Relevant eye safety risks will determine whether you should select basic, high-mass, high-velocity, or ballistic-rated safety glasses. The environment in which you will wear glasses or goggles and the strength of your prescription should both factor into your choice of safety eyewear.