Laser etching of Zeiss logo found on eyeglass lenses. Only seen at certain angle in the light : r/IRLEasterEggs
ZEISS Lens Cleaning Spray, Twin Pack for Cleansing Optical Surfaces, Glass and Plastic Cleaner, for Glasses, Spectacles, Cameras, Microscopes, Digital Screens and Ski Goggles,120 ml (Pack of 2) : Amazon.co.uk: Health &