How are eyeglass lenses made?
The optometrist determines what degree of correction your eyes require and the geometry of the lenses. The production of lenses is a highly-automated process. The lenses start as blanks of optical plastic or glass material. These are machined, ground, and polished on a series of numerically-controlled machines that use the prescription data to guide them. The frames you select are also sent to the manufacturer. After the lenses have been ground to the prescription, the lens frames are measured. This information is used to guide another machine that cuts and shapes the lenses to fit the frames. Any optional coatings are applied to the lenses before they are inserted into the frames.
