How are sunglass lenses made?

Sunglass lenses are made through a series of controlled manufacturing and finishing processes. The main stages include raw material preparation, lens moulding, quality inspection, hard coating, tinting and the application of functional or aesthetic coatings. The exact process varies depending on the lens material, such as OM15, Polyamide or Polycarbonate.

At first glance, a sunglass lens may look simple. Premium sunglass lenses are the result of a carefully controlled manufacturing process that combines material science, optical expertise and advanced production technology.

For eyewear brands, understanding how sunglass lenses are made is essential: the manufacturing process varies depending on the material, shaping the types of lenses that can be produced and their applications. Choosing the right material for your project from the outset means understanding both its characteristics and the differences in how it is processed. Below, we explore these differences in more detail to help guide your choice.

As a trusted sunlens manufacturer, ZEISS Sunlens applies almost 180 years of optical expertise to the development of premium sunglass lenses. From the selection of sun lens materials to tinting and final coatings, every stage is designed to deliver consistency, quality and design flexibility.

Every lens starts with the right material. This first step has a major impact on the final result.

Different sunglass lens materials offer different advantages in terms of weight, optical quality, impact resistance, flexibility and tinting performance. That is why brands need to understand which material best supports the intended use of the product.

Today, brands can choose from a wide range of sunglass lens materials, including traditional options and more responsible alternatives.

• OM15 sun lenses are known for excellent optical clarity and strong tinting performance, making them a popular choice for premium fashion eyewear. A key strength is their tintability: immersing the lenses in dye baths allows distinctive colours and colour effects to be created.
• Polyamide sun lenses offer lightweight comfort, versatility, flexibility and impact resistance for fashion and sport applications.
• Polycarbonate sun lenses are valued for durability and high impact resistance, especially in performance eyewear. The material is melted and injected into molds, allowing the creation of complex lens geometries.  

ZEISS Sunlens also offers a portfolio of polyamide and polycarbonate sun lens materials made with partially bio-based or bio-circular inputs (mass-balance approach).

Selecting the right material is the first step in creating premium sunglass lenses that meet brand, design and performance expectations.  

Many plastic sunglass lens materials are lightweight and impact resistant, but they can be more vulnerable to scratches than mineral glass.

To improve surface durability, premium lenses receive a hard coating. This transparent layer helps increase scratch resistance while preserving optical clarity. It also prepares the lens for additional finishing treatments applied later in the process.

Hard coating is an important step in the production of sunglass lenses because it supports longer-lasting performance and a better user experience.  

Colour helps define the character of every sunglass collection, but the way it is introduced into the lens depends on the material. OM15 (i.e. CR-39) and injection-molded materials follow different colouration processes, which influence how solid shades and gradient effects are created.

CR-39: solid and gradient colours through dye-bath tinting

OM15 (i.e. CR-39) lenses are tinted after casting by immersing clear lenses in temperature-controlled dye baths. For solid colours, the entire lens is immersed to achieve a uniform tint, with the dye formulation, bath temperature and immersion time determining the final shade and intensity. For gradient colours, controlled variations in immersion depth and duration create a smooth transition between darker and lighter areas. Different dye baths and repeated tinting stages can also be combined to produce multicolour effects.

Injection-molded materials: solid colours within the material, gradients through dye-bath tinting

For thermoplastic materials such as polyamide and polycarbonate, solid colours are incorporated into the raw material before injection moulding. Colourants are blended with the polymer, which is then melted and molded into lenses. The colour is therefore integrated into the lens material.

Gradient effects are created after moulding by immersing the lenses in dye baths. The starting lens differs depending on the desired result: a single gradient is produced from a clear lens, with controlled immersion creating a gradual transition from darker to lighter areas. A double gradient starts with an already coloured lens, to which a second colour is added through dye-bath tinting.

Understanding these differences helps brands evaluate colour possibilities alongside material performance from the start of a project. The desired shade, gradient effect and intended application should be considered together when selecting the most suitable lens material.

To learn more about lens colours and tint options, read our dedicated article.

Premium sunglass lenses result from a combination of high-quality raw materials, precise manufacturing, strict inspection and carefully managed finishing steps.

For brands, understanding how sun lens materials are transformed into finished lenses makes it easier to choose the right solutions for each collection. It also highlights the value of working with an experienced sun lens manufacturer that can deliver consistency, quality and technical know-how.

ZEISS Sunlens combines optical expertise and advanced manufacturing capabilities to produce high-quality sun lenses for a wide range of applications, supporting eyewear brands in developing products that combine design, performance and reliability.