ONO'S Carabelle Polarized Bifocal Sunglasses with Black Frame and Gray Lensstar rating 4BarryJuly 22, 2010The bifocal sunglasses have proven to be very durable in rough operating conditions around the yard while providing a comfortable experience during long distance drives. The only issue has been the rubber nose guards: they have torn and fallen off resulting in two exposed plastic knobs on each side.