Traditional progressive lens manufacturing starts with thick semi-finished blanks. The back side of the lens is then ground using a technique called surfacing that creates a contoured surface with rough craters. A lap tool, usually aluminum, is covered with an abrasive pad and is rubbed against the rough back surface to smooth it in a process called fining. Finally the same process is repeated again with a different abrasive pad to make the back surface transparent. This final process is called polishing.

DEFINITY™ Lenses are manufactured using Essilor® semi-finished blanks, which include a special progressive front surface. Custom design software calculates the progressive curves needed for the back surface to optimize the performance of the lens. A new manufacturing technology called freeform machining then precisely cuts the progressive curves into the back surface of the lens. Even the periphery of the lens is optimized with aspheric or atoric curves depending upon the patient’s prescription. This precision machining creates a surface so accurate that only a brief polishing step is needed after cutting to finish lens fabrication. GEMCOAT®, a high performance antireflective coating, may be applied after polishing. It is done in clean room conditions assuring the highest quality control for your patient’s lenses.