Sunglasses — they are an essential part of looking cool, as well as keeping the sun out of your eyes, especially when driving on those summer road trips. However when thinking about looking cool and driving, the Food and Drug Administration rarely comes to mind too.

However, FDA regulates sunglasses as a medical device. While this is a low-risk medical device (especially when compared to a pacemaker), this is a product that receives a moderate amount of attention from FDA. It is one of the few devices with a performance standard written into federal regulations: impact-resistance lenses, as determined by the drop ball test.

Yes, the “drop ball test,” which essentially consists of dropping a “5/8-inch steel ball weighing approximately 0.56 ounce … from a height of 50 inches upon the horizontal upper surface of the lens.” 21 C.F.R. 801.410(d)(2). If the lens breaks, then it fails the test and if a sufficient number of lenses in a lot fails, then the lot is deemed adulterated (unlawful).

FDA commonly tests imported sunglasses to verify that they comply with the drop ball requirement. If they fail to do so, FDA will take an enforcement action against them by issuing an import refusal. FDA generally will also impose an additional import expectation by requiring the importer to conduct additional testing of future shipments of glasses from the same manufacturer to prove that the lenses pass the drop ball test requirement. This process is referred to as an import alert, and the testing expectation continues indefinitely until FDA is persuaded that the future imports will comply with the drop ball requirement.

So on this National Sunglasses Day, don’t forget to thank FDA while looking cool like Maverick from Top Gun and protecting you from shards of glass in your eyes.