When I was working for a living all the guys who wore glasses had to start wearing safety glasses. I did a little research and found that the lower cost glasses had some sort of polycarbonate glass that was scratch and chip resistant. Top of the line was tempered glass. So I got the tempered glass and have continued wearing the same tempered glass lenses even after retirement. The PC glasses would start to chip,scratch,and get cloudy and since you only got one pair a year that was what you were stuck with until the following year. Frank
