To be compliant with the standard, the shield must pass tests on clarity, light transmittance, lack of optical distortion, impact resistance and even flame resistance as well as some other characteristics. Test procedures are specified in minute detail.
For example, there can be no sharp edges, the material cannot be prone to changes such as weakening, discoloration or becoming brittle with age or exposure to sun or common substances.The lens material of a non-corrective lens must not have prismatic effect greater than 1/8 diopter—meaning it must be optically correct for someone who does not need corrective lenses. This testing is done under American National Standards Institute (ANSI) Z87.1 specifications though eye protection devices for motorcycle operator use do not have to meet the entire Z87.1 standard.An eye protection device must provide a clear field of vision spanning a minimum of 105 degrees for peripheral vision. A clear lens must transmit not less than 85 percent of visible light; a tinted lens can transmit less than 85 percent of visible light, but not less than 20 percent. Tinted lenses cannot distort colors.Impact resistance is tested by dropping a 1.56 ounce steel projectile with a conical point directly on the lens from a height of 14 feet. The lens passes the test if it cracks or is penetrated, but the impactor does not pass through or remain lodged in the lens and no pieces or particles break free of the lens on the eyeward side.Plastic lenses are also subjected to a flammability test. To pass, the lens must either be non-flammable or, if it does burn, have a flame propagation rate of 1” or less in 20 seconds.Lens materials are also required to be able to washed with “ordinary household detergents” without deterioration.Compliant lenses must be permanently imprinted or marked with “VESC 8” or “V8” such that the mark does not interfere with the field of view and tinted lenses must bear the inscription, “day use only.”Of course, this is really about much more than a piece of your gear meeting some bureaucratic set of standards. Your eyes are irreplaceable and eye injuries can happen in an instant in an environment where flying road debris, rocks, bugs, falling foliage from roadside trees can happen at any time.Motorcycle eye protection is an absolute must; whether required by law or not, don’t ride without it and always use gear that meets the standards.