How Glasses and Contacts are made

T1: According to the Vision Council of America, about 75% of all adults in America wear contact lenses or prescription glasses. But how are these vision correcting tools made?

T2: The lenses used in eyeglasses are made in labs where they start off as blank pieces of glass or plastic. This blank piece has a flat back and a curved front, the lab technician will then take this glass and cut it at the correct angle to achieve the necessary angles.

T3: They are then edged perfectly to fit into the glasses frame of our choice. The science of light refraction to create focus levels for different vision prescriptions is something that requires years of study and practice.

T4: Contacts were originally made in the 1800s using wax or blown glass! The beginning of soft contact lenses came in the 1960s when “hydrogels” were developed that could be molded. Hydrogels are simply water-loving polymers.

T5: Today we use “silicone hydrogel’ lenses which allow for great oxygen permeability and liquid retention. Two methods are used for making these lenses: Lathe Cutting and Injection Molding.

T6: Lathe Cutting involves a process where hard disks of the lens material are shaped using a lathe and then put through the process of polishing and hydration. Injection Molding heats the contact material until it is a liquid and is then injected into molds.

T7: Here is a link to an episode of How Its Made where they talk more in-depth about the contact lens manufacturing process. https://www.youtube.com/watch?v=62tha1Kxa2c

http://www.glassescrafter.com/information/percentage-population-wears-g….

http://www.glassescrafter.com/information/how-prescription-glasses-are-….