Prescription lenses for glasses are made using specialized and precise processes. The general process is detailed below:
1: Eye exam:
The first step is to perform an eye exam to determine the required lens prescription. This is done by measuring the focal distance and the curvature of the eye's cornea.
2: Lens design:
With the required prescription in mind, a computer-aided design (CAD) program is used to design the shape of the lens and the necessary tilt angle for vision correction.
3: Material selection:
The choice of lens material depends on the type of correction needed. For example, lenses to correct myopia are usually made of plastic, while lenses for hyperopia correction may be made of glass.
What material are prescription lenses made of?
Prescription lenses can be made from different materials, and the choice depends on several factors, including the prescription, the user's lifestyle, face shape, and budget. Some common materials used to make prescription lenses are:
- Plastic: Plastic lenses are the most common due to their low cost and light weight. These lenses can be made from different types of plastic, such as polycarbonate or CR-39, and are ideal for people with low to moderate prescriptions.
- Glass: Glass lenses are heavier than plastic ones but offer greater optical clarity. They are suitable for people with higher prescriptions and are also scratch-resistant.
- Polycarbonate: Polycarbonate lenses are thinner and lighter than glass and plastic lenses, and they are also more impact-resistant. They are a popular choice for people with an active lifestyle or those who need safety lenses.
- Trivex: Trivex lenses are similar to polycarbonate but offer greater optical clarity and scratch resistance. They are ideal for people with moderate to high prescriptions.
It is important to keep in mind that each lens material type has its own advantages and disadvantages, and it is important to discuss with a vision health professional to determine the best option for each individual.
4: Lens molding:
The lens is molded from a block of material. First, the block is cut into the general shape of the lens, and then a precision milling machine is used to shape the lens into its final form.
5: Lens polishing:
After the lens has been molded, it undergoes a polishing process that removes any roughness or imperfections on the lens surface. This ensures the lens is completely transparent and free of distortions.
6: Lens coating:
Finally, the lens undergoes a coating process to reduce reflection and improve the lens's durability. This involves applying a thin layer of coating materials, such as titanium dioxide or magnesium fluoride, on the lens surface. This is where the necessary treatment is applied, such as anti-reflective, blue light filter...
After these steps, the prescription lenses can be fitted into a glasses frame to create a complete pair of glasses. It is important to note that the manufacturing process may vary slightly depending on the manufacturer and the type of lens being produced.
At Gafas de Óptica, our lenses are organic, with hardened treatment and anti-reflective coating always included.
