L&T: In the Lens Lab

May
2002

Not All Kids' Stuff



Not All Kids’ Stuff

Testing the safety of children’s frames

By John Young

Licensing and branding is used to market products via consumer trust. That motive drives branding in all eyewear and it takes on special meaning when it comes to selling eyewear to children. But should that trust extend to the virtues of eyewear licensed in the name of those brands? On that note everyone involved in the selling of eyewear to children needs to be concerned with the safety of such frames.



As part of a special 20/20 magazine investigation, we tested the quality and safety of several popular children’s frames here at COLTS Laboratories. Seventeen popular models representing four manufacturers were used in the test. In the interest of confidentiality, the manufacturers’ names will not be mentioned, (they will be represented as A,B, C and D) nor will their frames be seen in photos used in the article. Our task was not to rank specific frames in the market based on their safety and quality, but to evaluate whether the frames our industry produces for children generally meet the safety needs of their wearers.

The tests we conducted are used commonly in the evaluation of safety and durability in both the U.S. and Europe (cosmetic inspection, high-mass impact, high-velocity impact, corrosion, artificial perspiration, endurance, UV exposure and flammability). The “High-Mass” and “High-Velocity” impact tests we used are found in the American National Standards Institute (ANSI) Z87.1, which is the eye and face protection standard adopted by Occupational Safety and Health Administration for the workplace environment.

Safety is always a main concern when fitting children’s eyewear, which is why polycarbonate and Trivex lenses are recommended heavily for younger patients (see the Lens Choices feature in this issue). Of course, we cannot expect a frame to stop a projectile by itself. The lens is supposed to do that job. However, it is equally important that the lens stay in the frame during impact. That is part of what we tested here.

While our tests for this report focused on the frames, we did find an interesting issue with the lenses used in children’s eyewear. Most polycarbonate lenses for children’s frames are dispensed with center thicknesses (CTs) of 1.5mm. In our tests we found the “High-Mass” projectile penetrated lenses at this thickness. This lens would not meet ANSI Z87.1 safety standards, even if the frame it’s in does. Even though there is no requirement for fitting kids frames with 2.0mm CT polycarbonate lenses, it certainly makes sense to offer children and adolescents as much protection for their eyes as possible. (We didn’t get information for Trivex due to the limited number of frames in this study.)

In testing the children’s frames (see Figure 1 for complete results), we found three of them had excess play in their hinges. But the balance of the models passed our “Cosmetic Inspection” test, which is designed to assure the following:
• there are no sharp edges left from molding on the plastic frames;
• coatings are intact without crazing, peeling or runs and that there are no scratches, digs or other blemishes;
• the hinges have been assembled properly and there is a good fit between the front and temple;
• screws are tight and general alignment is satisfactory.
In all there are 24 points of inspection on each frame.

The “High-Mass” test involves dropping a 500-gram (1.13 lbs) weight with a pointed end onto the lens of a frame in the worn position (see Figure 2) from the height of 50 inches. The test is designed to determine whether the frame can retain the lens during impact. All but two of the frames we put to this test retained the lenses. Not bad for frames not designed for safety.

The “High-Velocity” test consists of a ball propelled directly at the Alderson head-form wearing the frames at a speed of 150 feet per second (102 MPH). This time, four frames failed.

The “Corrosion” and “Artificial Perspiration” tests are basically chemical evaluations duplicating actual conditions. In the “Corrosion” test a salt-water solution is used to soak the frames, which are then left out for a length of time. This could represent the environment of an eyeglass wearer living in an oceanfront community. The attempt to duplicate perspiration in the second of the chemical tests is pretty self-explanatory. Coatings bubbled, discolored or came off the frame in 10 of the 17 frames we put through these tests.

The “Endurance” test is designed to ensure that all of the frame parts will remain intact for the life of the frame. This test is especially important with children’s frames due to kids’ active lifestyles. To conduct the test, a device holds the frame by one of the temple ends and rotates the other temple end (see Figure 3). All of the frames we tested passed this test.

The “UV Exposure” test shows us what we can expect of frame performance in the sun—a good test since kids spend so much time outdoors. After 48 hours in the harsh UV environment of a Xenon Arc Lamp the samples are removed and inspected for color loss as well as cracking or blistering on the surface of the frame parts. There were four failures in this test.

Finally, the “Flammability” test is designed to assure that if a child gets too close to a flame, fire or other extreme heat, the frame won’t ignite or combust on its own. Fortunately, all of the frames we studied did well on this test.
Overall, one frame manufacturer passed nearly all of the tests while one or two others didn’t do as well. This illustrates the difference in both quality and lens retention capability among children’s frames. It is up to the dispenser to ensure they are fitting children with the best frames in terms of quality and safety.

John Young is an ophthalmic lens expert with more than 25 years experience in the optical industry. He has worked for several lens manufacturers, including American Optical and Essilor, and is the former technical director of the Optical Industry Association. His company, COLTS Laboratories, is a Clearwater, Fla.-based independent lens testing facility designed to provide thorough and accurate quality and performance evaluations of spectacle lens products. His clients include lens manufacturers, wholesale labs, independent research organizations, large retailers and independent dispensers. The lab was the first U.S. ophthalmic testing laboratory accredited by the American Association for Laboratory Accreditation. It is also a Safety Equipment Institute-accredited eye protection/safety test lab. Young can be reached by phone at (727) 725-2323 and by email at
john@colts-laboratories.com.

 

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