Cheap spectacle lenses are composed of different materials. Modern lenses are primarily made from ground plastics. They are traditionally processed in an optical laboratory but there are also optical shops today that can create custom lenses on-site.
The first eyeglass lens was made using transparent beryl and quartz. For many years, the manufacture and use of glass or mineral based lenses were the norm. Today, more than 80 percent of all manufactured cheap spectacle lenses are made from ground plastics.
The Key Ingredients of Cheap Spectacle Lenses
Round plastic is the chief component of modern lenses. This material is also called plastic blank and grounded to fit the specific shape of the frame. The plastic blanks are grounded to achieve the right thickness and power. Every prescription glass lens is unique because it is made to suit the vision requirements of the wearer.
Apart from the round plastic blanks, other materials used to create cheap spectacle lenses include adhesive tape, a lead alloy base in liquid form, metal, and tinting or shading treatments. Essentially, these are the basic materials of a typical eyeglass lens.
Stages of the Lens Manufacturing Process
Modern cheap spectacle lenses are made in an optical laboratory. The modern process is usually aided by computers to ensure accuracy. When your prescription has been received at the optical manufacturing site, the specs would be entered into the computer. The exact calculations of the lens design and power will be provided by the computer.
Plastic blanks are already grounded into different curves. Based on the information in your prescription, the lab technician selects the appropriate plastic blanks with the right curve. However, the technician still needs to grind the back of the lens to get the right specs indicated in your prescription. A machine called curve generator is used to do this job.
After grinding, the cheap spectacle lenses will undergo polishing. They are then placed in an edge grinder for proper shaping. This is important so that the lenses will fit into the prescribed frames. Part of the process includes beveling so that the lens can be secured into the rim edges of the frame.
Application of Tint for Cheap Spectacle Lenses
After the lenses have been grounded, shaped, and polished, the next step is the application of tint or shading. This step is done before the lenses are fitted into the frames.
The laboratory technician will dip the polished lenses into a heated metal bin. This bin is filled with the required tinting color or shade treatments. Tinting is an important procedure to give color to the lenses. The process also increases the ability of the lenses to protect your eyes from ultraviolet rays of the sun and glare. The shading treatment also provides added strength to your cheap spectacle lenses. It also makes the lenses scratch resistant.
The production of lenses started in the medieval ages when the first magnified looking glass was invented. Due to advances in technology, the production of lenses has become faster and more efficient. These advances paved the way for the mass production of cheap spectacle lenses.