What is the difference between scratch proof and scratch resistant?

What is the difference between scratch proof and scratch resistant?

In 1971, the Food and Drug Administration published a new policy that stated that prescription lenses should be impact-resistant by February of 1972. Manufacturers starting switching to polycarbonate, or plastic, lenses, that have been more durable, less expensive and lightweight, but also easily found scratches. Scratch-resistant materials are present in anti-Starch coating either as binders,…