Safety glasses are an essential part of personal protective equipment (PPE), helping to protect against hazards such as flying debris, chemical splashes and dust across a wide range of industries.
With workplace risks evolving and protective eyewear standards having been updated, choosing the right eye protection is more important than ever. In this guide, we’ll break down everything you need to know about safety glasses, including the latest UK standards, key features to look for, and how to select the best option for your environment.
When choosing safety glasses, it’s important to look for products that meet recognised UK and European standards.
For many years, the EN 166 standard was the benchmark for protective eyewear. It covered essential requirements such as optical clarity, impact resistance and durability.
Since 11 November 2025, EN ISO 16321 has replaced EN 166 for new certification in the UK and Europe.
Key improvements include:
What this means for buyers: You may still see EN 166 on some products already on the market, while newer models are increasingly certified to EN ISO 16321.
It is important to identify the risks involved in any given scenario. Here are some examples:
A thermal risk can occur when someone is exposed to molten metal or hot solids in industrial environments. This could include splashes of hot liquid metal or contact with hot solid particles. The ‘9’ marking indicates protection against molten metals and hot solids. Under EN ISO 16321, this marking no longer applies to goggles, because molten metal presents a risk to the entire face rather than just the eyes, so face protection may be required depending on the application.
Mechanical risks typically arise from operating machinery or using tools. The risk associated here is with sharp particles such as metal chips and shards from grinding work and tools, and high kinetic energy.
Under EN ISO 16321-1, impact markings have changed from the older EN 166 system, with the new standard also introducing minimum protection zones based on the speed of potential projectiles. For example, impact level C requires an Orbital Protection Zone (OPZ), level D requires an Extended Orbital Protection Zone (EOZ), and level E requires a Face Protection Zone (FPZ). In simple terms, the higher the impact speed, the larger the required area of protection.
Optical radiation can be a risk in many fields of work including medical, industrial and commercial. Here, surgical procedures, gas and electrical welding and other steel processes could impose optical radiation risks. The risk linked to radiation also includes ultraviolet, infrared and visible light. It is crucial to protect the eyes from such radiation because it can cause burns and lesions. There are many different risks which each have a different symbol and offer various levels of protection against optical radiation.
A chemical risk is posed when a hazardous substance is projected or is present in the environment. Examples include aerosols, dust, liquids, gases or vapours. Such risks are often present in the medical, agri-food and waste management industries. Symbols to look for include: 3 for droplets and splashes, 4 for large dust particles and 5 for gases, vapours, smoke, fumes and fine dust particles. These markings are more commonly associated with enclosed eye protection such as goggles, depending on the hazard
Where an electrical risk is present, a face shield is typically required, often used alongside other appropriate PPE. The face shield must not have any metal parts and must be completely rounded featuring no sharp edges. There could be severe consequences of an electric shock such as burns to the cornea, retinal lesions and conjunctivitis. Where relevant, marking ‘8’ refers specifically to protection against short-circuit electric arc and should not be taken as a general marking for all electrical hazards.
Light is made from many different wavelengths. The light we see is known as the visible spectrum of light. There are many other waves, some of which we cannot see, such as Ultraviolet. When it comes to eye protection, the main concern is exposure to energy from sunlight and artificial light sources. These include UV, Infrared and the visible spectrum. The human eye can typically detect wavelengths between 380 and 700 nanometres. These wavelengths reflect off various surfaces to produce the visible spectrum of colours.
As wavelengths of light become shorter, they build more energy and are therefore more harmful. The sun's UV light has a shorter wavelength than our visible spectrum and retains more energy. We know that UV light can cause sunburn to our skin and it can also damage the eyes over time. Exposure to invisible UV light can build up over time and can have a detrimental effect on our eyesight. Wearing safety glasses whilst working outside, particularly on bright sunny days, where the product specification includes UV protection, will offer protection against these harmful rays.
Modern safety glasses are designed with both protection and comfort in mind, often featuring lightweight materials, anti-fog and anti-scratch coatings, and improved ergonomics for all-day wear. Many leading brands offer safety glasses designed to balance protection, comfort and lens performance across a wide range of industries.
Many modern lenses also include anti-fog and anti-scratch coatings to improve visibility and durability in demanding environments.
A clear lens is a great all-rounder and a very popular choice. They offer as near to natural vision as possible and are suitable for a wide range of indoor tasks, with some models also offering UV protection.
The smoke (grey) lens provides excellent colour recognition, reduces glare and can enhance contrast and depth for better perspective. They are often chosen for outdoor work in bright conditions, although visible light transmission and UV performance will vary by product.
Yellow lenses are often used in low light conditions, particularly at dawn, dusk or indoors. They can enhance contrast and make things appear brighter for better visibility. Performance varies by lens type and coating, so these features should always be checked against the individual product specification.
A polarised lens can reduce glare, which helps minimise fatigue and visual discomfort caused when sunlight reflects from surfaces such as glass, car paint or water. Ideal for wearing outside, polarised lenses can be useful in bright environments, depending on the task and the product specification.
Safety glasses are designed for all-day wear and properly selected, correctly fitted safety glasses are not expected to harm eyesight. However, poor fit, unsuitable lens tints, scratches, fogging, or prolonged focus without breaks can still contribute to eye strain, headaches and fatigue. Choosing high-quality eyewear with advanced lens coatings and a comfortable fit can help minimise these issues, alongside taking regular breaks when needed.
You can browse the full range of safety glasses available at SHD Medical here.
Sources:
https://www.uvex-safety.com/en/knowledge/safety-standards/safety-glasses/
https://www.bsigroup.com/en-GB/insights-and-media/insights/blogs/a-new-era-in-eye-protection-understanding-en-iso-16321
https://www.bolle-safety.com/gb/insights/normsandstandards.html
https://science.nasa.gov/ems/09_visiblelight/
