Can an employee refuse safety eyewear because they wear glasses?

No. The employer’s duty is to provide protection that is suitable for that wearer — for a prescription wearer, that usually means prescription safety eyewear — and the employee’s part is to wear what is provided. A comfort or fit problem is a suitability issue to fix, not a ground for opting out.

Are "safety style" frames from an opticians automatically compliant?

Only if the complete pair carries the EN 166 markings the task demands — frame and lens, rated by the lower of the two. A robust-looking frame with unrated lenses, or CR-39 lenses where the task needs grade F, is not compliant however it looks.

What about prescription sunglasses outdoors?

Tint and protection are separate questions. Outdoor tasks with an eye hazard need marked protection with the appropriate filter scale number — ordinary prescription sunglasses carry neither the impact grade nor the certified filter designation.

Do contact lens wearers escape the problem?

They simplify it — a contact lens wearer can use standard (non-prescription) certified eye protection. The assessment still decides the grade and fields; contacts only remove the need for prescription lenses in the protector itself.

Can Employees Wear Their Own Glasses as Safety Glasses? — Certus

No — everyday spectacles are not tested or marked to EN 166 and provide no rated protection. What the law expects instead, and the three compliant routes for prescription wearers.

Certus is a UK platform for managing prescription safety eyewear compliance to EN 166, covering hazard assessments, ordering, optician verification and certificate records. Operated by Certus Safety Ltd, registered in England and Wales, company number 17364362.