All ophthalmic lenses must pass the ball-drop test.
A steel ball is dropped onto a Ray-Ban lens from 50 in.
The FDA’s Impact-Resistance Regulation from 1972 was revised last year and its Effect on the optical industry remains significant.
On January 1, 1972, the U.S. Food and Drug Administration (FDA) mandated that ophthalmic lenses be impact resistant. This regulation was revised in 2014 and while no significant changes were made, its influence continues to ripple through the eyewear market. Here’s what you should know.
Under the rule, all ophthalmic and sunglass lenses must be impact resistant, unless a physician or optometrist finds that impact-resistant lenses will not fulfill the patient’s visual needs. This information must be noted in the patient’s record and they must be given a written copy.
WHO’S THE MAN(UFACTURER)?
One of the big questions concerning impact resistance is, “Who is responsible for testing the lenses?” The answer is that the lens’ manufacturer is responsible, but since lens manufacturers, labs, and ECPs all often fabricate eyewear, who is “the manufacturer” of a particular pair of eyeglasses? In the FDA’s guide for impact-resistant lenses (fda.gov/RegulatoryInformation/Guidances/ucm070579.htm), it states that the manufacturer is defined as any person or firm who puts a lens into its final form for use; or who cuts, grinds, heat treats, bevels, coats, or otherwise modifies a lens’ physical and/or chemical properties.
Plastic lenses and non-prescription glass lenses can be tested at the uncut or finished stages. Prescription glass lenses, however, must be tested at the finished stage. In addition, modifications such as drilling holes and applying coatings may weaken lenses, so they will need to be checked for impact resistance before their delivery to the patient.
In short, what this all means is that retail laboratories and ECPs that perform some or all of these processes are “manufacturers” and, therefore, are responsible for impact-resistance testing.
PASSING THE TEST
How do ECPs make lenses im-pact resistant? Thankfully, plastic lenses are inherently impact resistant due to the nature of the material. Glass lenses, however, must be tempered after edging. There are two ways to temper glass lenses: heat treating and chemical treating. Heat treating is done by placing a lens in a kiln that first heats, then rapidly cools it. Chemical treating involves immersing a lens in a molten salt bath for 16 hours. The next step is the actual impact testing. For dress eyewear, the impact resistance test is performed by dropping a 5/8-in. steel ball onto the lens’ surface from a height of 50 in.
For years, ophthalmic dress lenses had a minimum thickness requirement, regardless of the lens material used. Today, the FDA no longer has such a requirement. Still, it should be noted that CR-39‘ and Crown Glass lenses will not consistently pass the ball-drop test unless they are at least 1.5-2mm thick. Polycarbonate and other plastic materials, however, can be made with centers as low as 1.0mm. Improvements in coating technologies also allow for thinner plastic lenses.
The FDA does not regulate other forms of eyewear such as safety glasses and sports glasses (including swim goggles, ski goggles, and racquetball eye guards) as devices unless they make sun protection claims. However, the Occupational Health & Safety Administration (OSHA) does have mandatory standards for proper safety eyewear in the workplace. In addition, The American National Standards Institute (ANSI) also provides recommended standards for both ophthalmic and high-impact lenses and ASTM International has issued voluntary worldwide standards, so these organizations should also be on your radar.
FOR THE RECORD
The FDA also requires extensive record keeping following an eyewear purchase. Copies of invoices, shipping documents, and records of sale or distribution of all impact-resistant lenses, including finished eyeglasses and sunglasses, must be kept by the manufacturer for three years after the sale. The records must include the names and addresses of the people purchasing prescription eyewear. Sales records of nonprescription eyewear don’t need to be kept.
One final note: It is important to remember that all lenses lose their impact resistance due to surface blemishes over time. The number and depth of scratches will weaken the lens proportionally and reduce its impact resistance.
Randall L. Smith is the Opticianry Program Director at Baker College in Allen Park, MI.