Progressive no-line bifocals also contain two prescriptions but gradually transition between the prescriptions to provide an uninterrupted vision field. There is no visible line like in traditional bifocals. This makes them more aesthetically appealing but takes more getting used to as the wearer has to adjust their head position to bring objects into focus. https://webyourself.eu/blogs/793180/Prescription-Lenses-The-Many-Forms-and-Functions-of-Corrective-Eyewear