The Food and Drug Administration (FDA) requires shipments of nonprescription sunglasses include the “Drop Ball Test” certificate. This certificate confirms the safety and durability of the lens for impact resistance. Consumers, manufacturers, and sellers are required to test a batch of lenses prior to shipping them. The number of lenses tested for impact resistance within each batch or lot varies depending on material and type of lens being shipped. Records of the drop ball test must be maintained for a minimum of three years from the date of shipments for the FDA upon request.
The FDA does not require a particular method for making eyeglass lenses impact resistant, however the lens must adhere to the regulations outlined in 21 CFR 801.410(d)(2) which reads “In the impact test, a 5/8-inch steel ball weighing approximately 0.56 ounce is dropped from a height of 50 inches upon the horizontal upper surface of the lens. The ball shall strike within a 5/8 inch diameter circle located at the geometric center of the lens. The ball may be guided but not restricted in its fall by being dropped through a tube extending to within approximately 4 inches of the lens. To pass the test, the lens must not fracture….”