Prescription Safety Eyewear: Are you protected?

An alternative material to polycarbonate is CR39 (Columbia Resin 39), a plastic polymer commonly used in the manufacture of eyeglass lenses. Unlike polycarbonate, CR39 requires a UV coating to be added to protect eyes from the sun’s harmful rays. A UV filter is extremely important, especially if you or your employees work outside.

Although commonly used by high street opticians in prescription safety eyewear, CR39 only offers increased robustness conforming to EN 166S similar to that of toughened glass. Many high street prescription safety lens ranges start with CR39 and only ‘upgrade’ to polycarbonate upon request. This is not common knowledge and many wearers assume they are protected just like their peers.

It is important to note that CR39 is ideal for everyday glasses and Visual Display Users (VDU) but it's not suitable for workplaces where impact poses a risk.

For uvex safety is paramount. Ensure your prescription safety glasses will perform should the unthinkable happen by checking the lens on your glasses to see what markings it has. This information will be either at the top of the lens or on the side. Look for the letters S or F; if you can see an S your glasses are likely to be CR39.

Safety prescription glass lenses will have markings to:

1. identify the manufacturer (in uvex’s case W)
2. state the optical quality e.g. a 1, and 
3. the impact strength e.g. S or F

This information will be either at the top of the lens or on the side (see diagram). Look for the letters S or F: if you can see an S your glasses are either CR39 or toughened glass, if it is F then they are polycarbonate. For industrial workplaces with a risk of impact, polycarbonate lenses should be selected.

_{This information will not be visible on VDU/office spectacle lenses.}