I purchased the 24K lenses for those days when I prefer the blue blocking aspects of the lense. These lenses are optically perfect. The coatings are tough and there are zero problems. The only issue is that the first couple of times you change the lenses it is difficult. Once you get the hang of it there are no problems. I highly recommend the 'armored' box case for these as you can literally drive over the case with your car and not hurt the glasses.