By Barry Santini ABOM
To protect for sun and safety, both the frame and the lens must be safety certified.
In this case, the frame, unlike dress eyewear, takes on as much importance as the lenses.
The ANSI Z87.1-2003 High Impact Safety Standard
Both the frame and lens require safety certification, what does that mean? The answers lie in the requirements set forth in an industry wide agreement called ANSI Z87.1-2003.
About every 10 years, the American National Standards Institute (ANSI), a private nonprofit organization, reviews ANSI standards. Z87.1 defines Occupational and Educational Eye and Face Protection. This standard has testing criteria for both frames and lenses and two levels of performance are defined; Basic Impact and High Impact.
For example, in addition to the high mass and high impact tests, the frame must have the ability to retain a 2.0 mm plano lens under high impact (not just a 3.0 mm plano) in order to earn the High Impact label. Also, prescription lenses must meet stringent standards. Here is a short example of Z87 requirements, for more details a complete copy of the standard can be ordered from ANSI directly at www.webstore.ansi.org. Frames that are labeled "safety certified" meet these very stringent requirements.
High Mass Impact and Retention Test: Pointed projectiles (500 g) are dropped 50 inches. Four samples must be tested and for all, no piece shall be detached from the inner surface of any frame component, and the test lens shall be retained in the frame.
High Velocity Impact and Retention Test: A steel ball (0.25 in) at 150-ft/sec velocity hits the frame. No contact with the eye of the head form is permitted as a result of impact. 20 samples must be tested of any frame component, and the test lens (2 mm poly plano) shall be retained in the frame.
Flammability: The front, temple, lens and removable side shield (if applicable) shall not burn at a rate greater than 76 mm (3 inches) per minute.
Prescription and Removable Plano Lenses
Basic Impact: Spectacle lenses shall be not less than 3.0 mm thick, except prescriptions that are +3.00D or greater in the most plus meridian in the distance portion of the lens which shall have a minimum of a thickness no less than 2.5mm. Spectacle lenses shall be capable of resisting impact (drop ball) from a 1-inch diameter steel ball dropped from a height of 50.0 in. The lens shall not fracture as a result of this test.
High Impact: When used in a frame marked Z87-2, the lenses shall not be less than 2.0mm thick is capable of resisting an impact from a 0.25 in diameter steel ball traveling at a velocity of 150 ft./sec. No piece shall be detached from the inner surface of the lens. In addition, the lens should not fracture.
Penetration Test (Plastic Lenses Only): Plastic spectacle lenses shall be capable of resisting penetration from a weighted projectile weighing 44.2 grams dropped from a height 50.0 inches. The lens should not fracture or be pierced through as a result of this test.
Optical Quality: Lenses shall be optically correct when measured for Prismatic Power, Refractive Power, Resolving Power, Haze, and Transmittance. The optics need to be precise in order to meet ANSI Z87 optics. (Note: optical characteristics may behave differently in the uncut and glazed versions, be sure to see test results for lens quality when glazed in their respective frames.)
Transmittance: Lenses shall comply with standard requirements for clear or general-purpose filters or special purpose lenses. The lens shade marking is determined by the light transmission or type of special purpose lens.
Look for the Markings to Know for Sure
Frames that pass the retention tests are stamped with the manufacturer's mark and "Z87" or "Z87-2". If the frame is intended for plano, it is marked Z87. If intended for both plano and prescription lenses, it is marked Z87-2. Therefore, for fames carried in a dispensary, where many customers will want prescription options, it makes sense to look for the Z87-2 marking. It adds flexibility to inventory and increases the opportunity for sales.
In a safety certified clear or sunglass, lenses are marked permanently. The different designations help the optician show their customers that lenses fabricated will meet either the Basic or High Impact test.
1) For Removable Lenses, the markings are as follows: The mark or logo indicates or identifies the manufacturer and compliance with Impact Testing Requirements.
An example of this is WX. The lens was supplied and tested by Wiley X and meets the Basic Impact Lens requirement. If the mark were WX +, then the supplier again is Wiley X and the "+" sign describes the lens as being compliant with High Impact lens requirements.
2) For Non-Removable Lenses, the markings are as follows: Only one marking on the frame front or one of the temples is required. As before, mark or logo indicates or identifies the manufacturer. The Z87 indicates compliance with the ANSI safety standard, there is a letter shade number, and a "+" indicates that it meets the High Impact Testing requirements.
An example of a non-removable lens would be: WX Z87 S+ and would translate to Wiley X (WX), ANSI Z87 frame (Z87), special purpose lens (S) or shaded, High impact lens (+). Photochromics are also allowed and designated with the letter V.
Safety is technical and complicated so relying on the dependability of a sunglass to meet the safety requirements require that it be properly marked. Wiley X is unique in the marketplace in that it is the only company that supplies all of its sunwear, Safety Certified.
Patients respond to discussions about protection of their eyes especially when combined with a pair of frames that they agree they look good in. After all, fashion and function must both work wonderfully together to make a difference in a new pair of eyewear for a patient to say "wow."