How Contact Lenses Are Made – Part 1
The process of manufacturing contact lenses can be split up into four separate areas – moulding or lathing, finishing, quality control and packaging. In Part 1 of this two part series, we’re going to take a look at the moulding and lathing processes.
When contact lenses are being created, there are two initial ways to create the contact lens – the moulding method and the lathing method. Both have their own benefits and both are still used to create contact lenses today.
Moulding – when contact lenses were first being produced by the moulding procedure, they were initially created by pouring a mixture of fluids into a rotating mould. The contact lens shape was created by both the mould itself and by how fast the mould was rotating.
Over the years, injection moulding was introduced, which is a much more reliable and easier means of creating contact lenses by moulding. In essence, the fluids are injected into a pressure mould at a high temperature, quickly removed and allowed to cool, with finishing taking place on a lathe. Extremely effective in creating high quality contact lenses in mass quantities, injection moulding has only been in use in recent years.
Lathing – A longer, but more finished process of creating contact lenses is by using a lathe for the full process. The contact lens material is mounted upon a lathe, which turns at a set speed and angle, allowing for the cutting tool to carry out its work and effectively make the actual contact lens. After the process, the lens is placed upon a separate machine where it is polished and coated to ensure no rough or uneven edges and to give it a safe finish.