Many of the same factors that make the wearing of safety glasses necessary can also lead to fogging: indoor and outdoor work, temperature changes, humid environments, assembly work around heated or frozen machinery. And because safety glasses are used while you are active, be it for a work task or participation in a sport or exercise activity, body heat and perspiration also contribute to the problem.
These factors cause moisture to coalesce on the surface of your lenses. Taking the time and effort to wipe them off can be problematic, especially if your safety equipment extends to gloves or a helmet. Worse yet, clearing fogged safety glasses can be hazardous; imagine if your lenses fogged while you were driving down the highway on a motorcycle, your hands involved in the operation of the bike, or working pincers to remove molten metal from a smelting oven. These are just two examples – there are hundreds more – of instances where fogging at an inopportune moment can lead to either vision impairment or distraction while you wipe off glasses when your hands (and your attention) should be on other things.
The permanent anti-fog coating option is commonly applied to both sides of a prescription lens when it is formed, or between sections of layered glass or plastic, depending on the material used. It is compatible with most but not all forms of standard and high index glass and plastic – individual availability will vary by the material. These coatings work by affecting the collection of condensation into bigger water droplets on a molecular level.
Temporary relief from fogging can be obtained by using one of several products that are applied to prescription lenses with a cloth or disposable wipe and then buffed dry. This is a good alternative for occasional use, if you encounter fogging conditions only periodically. The application is good for a finite period of time but eventually lessens in effectiveness as it wears off. Typically the anti-fog material is available in liquid, gel, or wax form.
Finally, several safety eyewear manufacturers utilize some form of ventilation system. This is a channeled frame design that routes air over and across the lenses, drying them off and/or venting moist air from a sealed frame and replacing it with cooler exterior air. Some heavy-duty designs, usually in goggle format, incorporate a small battery-operated fan for aggressive air movement and ventilation.
Visit Rx Safety to explore all your options in permanent, temporary, or active air ventilation systems, and enjoy hands-free, fog-free vision in your next pair of prescription safety glasses.