Manufacturing of Contact Lenses

How are these great creations manufactured?

There are several steps in producing contact lenses:

Step 1: Molding
The lenses are spin-cast where three fluids are poured into rotating molds. The polymerization of the fluids creates the hydrophilic plastic used in contact lenses. Another molding method used to mass-produce lenses is injection molding, where molten plastic is injected into a mold. New technology has made it possible for contacts to be finished in the molding process with no lathe cutting necessary.

Step 2: Lathe Process
The plastic circle is attached to a steel button that has a drop of molten wax on it. This is then placed on a lathe that spins at a very high speed, and a laser or diamond cutting tool cuts the rough lens to form the central posterior curve. The button is then moved to a lapping machine that polishes the lens surface. The process continues on a steel shaft called an arbor where the central anterior curve is made and polished.

Step 3: Finishing
In order for the lens to fit exactly in the user’s eye, a few more curves need to be ground. The peripheral anterior and posterior curves and intermediate anterior and posterior curves are made on the grinding machine. An emery paper is used to grind the smaller cuts, and the diameter of the lens is trimmed.

Step 4: Quality Control
Contact lenses come into contact with some very vital parts of your body, so constant inspection takes place in every step of the manufacturing process.

Step 5: Packaging
The lenses must first pass the quality control assessment, but once that is completed, they are ready to be packaged and shipped. The lenses are first sterilized, and then they are boiled in salt water for a long period of time to soften. After this is completed, the lenses are packaged in saline solution in glass vials. The saline solution imitates human tears and makes the contact lenses even softer for your comfortable usage.