What are glasses made of?

Glasses can be made of a variety of different materials, including but not limited to titanium, stainless steel, nickel silver, acetate and plastic. They can also be made of eco-friendly materials which are bio-based and recycled.

Glasses are made up of several components and therefore require a meticulous manufacturing process. It can take up to three weeks to turn a sheet of material into a finished frame.

The process involves several key steps. To create a pair of acetate frames, the production team first starts with a sheet of the material which they carefully sculpt into several parts, including the front of the frame and temples.

First of all, in order to create the front of the frame, the material is cut and shimmed to achieve the right thickness. Then, if needed, extra material is glued to specific areas of the design. It is then milled to remove any excess material. This helps to create the shape of the internal lens. The frame is then bent so that it is curved. Then the tumbling process begins, whereby the front of the frames are put into wooden barrels with coarse woods and pastes that, as the barrel rotates, gets rid of excess material and improves the overall finish. Next, the temples are cut and shaped from a slab of material. A wire core is inserted for added strength. The temples are then also tumbled before being connected to the front of the frame. The final design then goes through several rigorous final checks.

Metal frames, meanwhile, start with raw materials in the form of sheets, bars, or wires. To create the various components that will later make up a complete frame, the sheets of metal must first be cut. They are then stamped with the outline of the front of the frame before being carefully trimmed into shape and given a meticulous finish.

The metal bars are then processed which help to form essential components like the temples, hinges and fronts. The thickness of the bar is reduced using a process called turning. The bar is then bent and punched to achieve the desired shape.

Metal wire is mainly used to produce the rims (which support the lenses) of the metal frames. The coils are first unwound and then shaped accordingly using ‘hooping machines’.

All the components are put through a tumbling process at least once which helps to give them a smooth finish. They are polished and removed of any imperfections. The separate components are then connected together.

The manufacturing process requires a high level of quality control and precision – from machining and polishing to the putting together of components and the overall manual assembly.

Metal frames require an extensive range of surface treatments which help to enhance their aesthetic and ensure corrosion resistance.

There are a variety of different lens materials for your eyewear. Each type of lens material can assist in correcting refractive errors like short-sightedness, long-sightedness, astigmatism, or presbyopia.

Before finding out about the various lens materials, it is important to have an understanding of refractive index. Some materials are classified by the index of refraction, which specifies how quickly light travels through a specific material.

Put simply, the higher the refractive index, the more light is bent by the material, therefore less lens material is needed compared to a lens with a lower refractive index.

So essentially, for any eye prescription, the higher the refractive index the thinner the lens will be.

Lenses used to be made of glass but due to the fact they were uncomfortable, heavy and easily breakable, they have since been replaced by various plastic materials.

Glasses lenses are most commonly constructed from CR39 plastic which has excellent optical features. However, CR39 plastic lenses are often much thicker than other plastics due to the fact they have a low index of refraction of 1.5. This material is normally very affordable and recommended for people with lower prescriptions.

Polycarbonate is the most durable of the lens materials and therefore is ideal for sports lovers and those whose glasses are susceptible to damage. It comes with 100% UV protection and is normally recommended for rimless frames. Theses lenses have a refractive index of 1.59 which is great for people with a high prescription.

The mid-index plastic material at 1.6 is 20% thinner and lighter than low-index materials like CR39. It is suitable for medium power prescriptions.

A high-index plastic lens with a refractive index of 1.67 is around 33% thinner, whereas a lens with a refractive index of 1.74 will be around 42% thinner. They are best for people with a very strong prescription.

At Glasses Direct, we have a variety of lens packages suitable for different prescriptions which all come with a reliable scratch-resistant coating and depending on the package, anti-reflective and UV protection. You can easily find an option that best suits you and your requirements.