Monday 15th December, 2025
5-7minute read
Why the updated standard matters
At Stronghold Global, we know that protecting your team starts with getting the basics right. Eye protection is one of the most essential pieces of PPE, yet it is often underestimated or chosen without clarity. With the introduction of EN ISO 16321:2022, occupational eye protection standards have been significantly upgraded.
This update replaces the older EN 166 standard and reflects a modern approach to protecting workers’ eyesight across a wide range of industries and environments. It brings clearer testing, better fit, and higher levels of protection, making it easier to select PPE that genuinely keeps people safe while improving comfort and compliance.
For more than 20 years, EN 166 shaped the design and certification of safety eyewear in the UK and Europe. However, workplace hazards, roles, and the diversity of the workforce have evolved. EN 166 tested only two head sizes, had limited classification of impact resistance, and offered less clarity on optional features such as anti-fog, dust protection or chemical splash resistance.
EN ISO 16321 addresses these limitations, introducing a more inclusive and globally aligned approach to testing and certification. From November 2025, all new certifications will follow this standard, making it crucial for safety managers, procurement teams, and workers to understand the changes and their implications.
What’s changed at a glance
| Old standard | New standard | What’s different and why it matters |
| EN 166 and related filter standards (EN 170, EN 171, EN 172) | EN ISO 16321-1:2022 and associated parts | Focuses on occupational and educational eyewear. Specialist items such as laser protection, medical eye protection, solar-only eyewear, and arc flash face shields are now certified under separate standards, ensuring testing matches intended use. |
| Testing on only two head sizes (small and medium) | Six headform sizes covering small, medium, and large in both European and Asian head shapes | Covers around 95% of global head dimensions, delivering a more accurate and inclusive fit. Ensures eyewear stays in place and provides full protection across a wider range of users. |
| Impact resistance labels S, F, B, A | C (45 m/s), D (80 m/s), E (120 m/s) with optional high mass (HM) test | Updated levels give clearer distinctions between low, medium, and high energy hazards. HM test adds protection for heavier objects or higher risk environments. |
| Simple impact testing (e.g., drop ball) | Defined “protection zones” based on impact energy | Products are now tested against specific facial zones: Orbital Protection Zone (OPZ), Extended Orbital Protection Zone (EOZ), and Face Protection Zone (FPZ). Makes it easier to match eyewear to hazards. |
| Older filter markings for UV, IR, solar | Updated lens-filter codes | Clearer labelling allows workers to identify protection levels quickly, reducing guesswork. |
| Optional performance features with less rigorous verification | New optional features with stricter testing | Features such as anti-fog, chemical resistance, dust protection, splash protection, and heat resistance are now validated under more robust tests, ensuring claims reflect real-world protection. |
Key improvements under EN ISO 16321
One of the most significant changes is the approach to fit. By introducing six head form sizes, the standard ensures eyewear provides a secure, comfortable fit across a broad spectrum of face shapes. This reduces gaps where debris can enter, minimises discomfort, and improves compliance by encouraging workers to wear the PPE consistently throughout their shifts.
Impact protection has been refined and is now tied to energy-based levels and defined protection zones:
- Orbital Protection Zone (OPZ) for lower energy impacts
- Extended Orbital Protection Zone (EOZ) for medium energy impacts
- Face Protection Zone (FPZ) for higher energy impacts
These zones make it much easier for safety managers to select the right eyewear for their site hazards, from small flying particles to high-velocity projectiles. Optional features such as anti-fog coatings, scratch resistance, chemical splash protection, dust resistance, heat resistance, and protection in explosive atmospheres must now undergo more rigorous testing, providing reassurance that PPE performs effectively in real-world conditions.
What EN ISO 16321 does not cover
While the standard applies to everyday occupational and educational eyewear, specialist items remain under separate regulations, including:
- Laser protection eyewear
- Medical or surgical eye protection
- Solar-only sunglasses
- Electrical arc flash face shields
- Welding-specific PPE
Understanding these boundaries ensures that workplaces select the correct standard for each hazard type.
Why this matters for UK workplaces
Eye injuries remain a serious concern in the UK. According to HSE data, more than 800 eye-related incidents were reported in a recent year, and studies suggest that up to 90% of serious eye injuries requiring hospital treatment could have been prevented with suitable PPE. Poorly fitted eyewear or incorrectly selected protection is a major factor in these incidents.
Adopting EN ISO 16321-certified products ensures:
- Better fit for diverse teams
- Clear understanding of coverage and protection levels
- Reliable optional protection against chemicals, dust, heat, and other hazards
- Reduced injury rates and improved compliance
For companies in construction, manufacturing, laboratories, or maintenance, this can translate into fewer lost-time injuries, greater workforce confidence, and a measurable impact on productivity and safety culture.
At Stronghold Global, we are committed to ensuring our eyewear range meets the new standard. Our aim is to provide PPE that not only protects effectively but also fits comfortably, encourages consistent use, and supports safer, more productive workplaces.
For organisations reviewing their PPE now, this is the perfect opportunity to check that current stock meets EN ISO 16321 and that all future purchases reflect the latest requirements.
