What is the risk?
Anyone who wears regular glasses under a full-face mask faces more risk than is often assumed. The temple arms of ordinary glasses run along the sides of the head, exactly through the zone where the mask must seal against the skin. Those temple arms push the sealing edge away locally, creating a tiny gap. According to the Belgian professional association for prevention advisors Prebes, that gap is enough to let hazardous substances, vapours or fine dust seep into the mask, even if the wearer does not notice it.
A full-face mask only protects when the seal around the entire face remains intact. Once that seal is broken, the mask no longer meets the requirements of the European standard for full-face masks (EN 136), and in practice the protection it is certified for no longer applies. Employers who let staff work with regular glasses under a full-face mask thereby take a risk that conflicts with the general obligation to provide properly functioning personal protective equipment, an obligation laid down in similarly worded terms in labour legislation in most European countries.
What solutions exist?
The standard solution is a so-called mask spectacle kit or insert frame: a frame without temple arms that clips onto fixed attachment points inside the mask, separate from the sealing edge. Such a frame is combined with lenses matched to the wearer’s prescription. The process usually runs in a few steps: an eye test, choosing a frame that fits the specific mask model, grinding the lenses, and fitting them into the mask itself.
It is important that an insert frame is always specific to the mask model it is used in: a generic frame not designed for that model offers no guarantee of an intact seal and therefore does not solve the problem. Employers and users do well to check with the mask supplier whether a suitable insert frame exists, rather than simply sliding a pair of glasses under the mask. Contact lenses are an alternative for some glasses wearers, although they are not comfortable or suitable for everyone, and some workplaces have their own hygiene or safety rules regarding them.
Context
That visual correction is a point of attention when choosing respiratory protection is also recognised in independent professional literature. The Dutch Society for Occupational Hygiene explicitly names corrective glasses or contact lenses as a personal factor that plays a role in selecting protective equipment. The same professional guideline states that a face-fit test, which checks whether a mask seals properly against the wearer’s face, is necessary to ensure a good fit and must be carried out individually. That aligns with the core of the European standard: a full-face mask is tested and certified under EN 136 based on a complete seal along the forehead, cheeks, nose and chin. As soon as glasses disturb that seal, the protection falls outside the conditions on which the mask’s certification is based. That is why not only the mask itself, but also its combination with any visual correction, must be checked on the wearer’s face.
Source: Wearing regular glasses under a full-face mask not without risks, 2 October 2026
