The best defense against fogging is a high-performance anti-fog lens coating. The most reliable coatings employ dual-action properties. (Uvex Safety Eyewear photo)

Tips for Combating Fog on Safety Lenses to Improve Safety, Productivity

When safety eyewear fogs, workers have little choice but to remove it and wipe it clear, which can lead to repeated interruptions throughout the shift.

Fogging is the No. 1 problem faced by safety eyewear users. It occurs across industries—construction, manufacturing, chemical, utilities, oil and gas, and more—and across applications. In fact, if you've ever worn safety eyewear, you probably know that fogging on untreated lenses is nearly impossible to avoid.

But maintaining a fog-free view is vital to the well-being of workers and employers alike. When tasks are conducted with fog-obscured vision, workers risk eye injury and bodily harm. Catastrophic events often occur in the blink of an eye: a slip or fall; getting struck by equipment or caught in machinery; making contact with harmful chemicals or electrical current. An employer’s productivity and compliance are at risk, too.

With so much at stake, it's easy to see why safety managers need effective anti-fog solutions and why eyewear manufacturers strive to develop longer-lasting anti-fog (AF) coatings. But not all AF-coated lenses deliver the same level of protection or consistency, and until now lenses with anti-fog coating didn’t necessarily stand up to the demands of the workplace.

Recent innovations in anti-fog lens coating have dramatically improved performance. Here we look at the dangers and costs of fogging and the differences among lens coatings. Armed with this knowledge, safety managers can seek out coatings that deliver the consistent, long-lasting results required to keep workers safe and productive and to help protect employers' bottom lines.

Factors That Cause Fogging

  • Environmental heat and humidity. The most obvious cause: Existing moisture in the air adheres to the outside of the lens.
  • Worker exertion. As an individual's body temperature rises, the heat and sweat produced around the face need to dissipate into the atmosphere, typically fogging the inside of the lens.
  • Transitions between warm and cool environments. Whether moving from warm-to-cool or cool-to-warm environments, such worker transitions cause moisture to condense on the outside of the lens.
  • Lens washing. A lesser known cause of fogging, washing most anti-fog coated lenses erodes their AF properties, diminishing their capacity to manage water from the environment.

Impact on Safety
Whatever the cause, workers whose vision is obscured by fog cannot clearly see the hazards around them and are vulnerable to injury, from minor bumps to life-threatening harm. Similarly, workers who take off—and leave off—their eyewear to avoid the hassle of fog are vulnerable to eye injury from nearby hazards.

Keep in mind, safety eyewear protects not only from visible, physical hazards, but also from harmful visible and invisible light. The effects of overexposure to optical radiation range from eye fatigue, dryness, and irritation to short-term and permanent vision loss. In fact, long-term exposure to the sun’s ultraviolet rays is a leading cause of cataracts and blindness in the United States.1 Therefore, when workers remove their safety eyewear due to fogging, they face greater risk from physical and radiation hazards alike.

Impact on Productivity
Foggy lenses don't just reduce safety—they impact productivity, too. When safety eyewear fogs, workers have little choice but to remove it and wipe it clear, which can lead to repeated interruptions throughout the shift. When eyewear is removed, even briefly, in the work zone, work is interrupted and individuals are unprotected. When workers leave the site to safely dry their lenses away from hazards, productivity takes an even greater hit. The cumulative cost of fog-related interruptions can add up to a big reduction in productivity.

The Cost of Noncompliance
Foggy lenses directly impact compliance. It is not uncommon for workers to take off fogging eyewear—and leave it off—rather than deal with the ongoing hassle and distraction of fog. But when workers leave eyewear off altogether, not only are they risking eye injury, they are also noncompliant with safety regulations, which can incur hefty penalties. Because safety eyewear is a highly visible form of PPE, violations are easy for inspectors to spot.

While regulatory fines for noncompliance may seem sizable, consider the cost of noncompliance when it results in an eye injury:

  • The cost of lost vision to an individual is immeasurable, spanning medical expenses, diminished quality of life, and the reduced ability to earn a living.
  • Workplace eye injuries cost U.S. employers an estimated $467 million per year in direct costs.2
  • With indirect costs included, such as legal fees, judgments, and training new workers, the estimated total exceeds $934 million per year.3

Despite national and corporate safety programs, approximately 2,000 occupational eye injuries occur in the United States every day—more than 700,000 annually—taking a massive toll on workforce health and overall productivity.4 Yet most safety professionals agree: Nearly all occupational eye injuries could be prevented through the proper use of the appropriate eyewear.5

Anti-fog Solutions Differ Widely
While anti-fog solutions include wipes and sprays, the best defense against fogging is a high-performance anti-fog lens coating. Be aware that different manufacturers’ coating technologies work in different ways, with varying levels of success and longevity. Furthermore, the methods used for applying coatings vary widely, resulting in a spectrum of consistency and performance. When the reservoir of anti-fog agents is shallow, for instance, those agents are easily wiped or washed away after the first few uses. Likewise, a coating whose application isn't closely monitored is likely to deliver inconsistent anti-fog performance and distorted lens optics.

Many anti-fog products look good out of the box, but when coating formulations or application methods lack effectiveness or durability, safety eyewear becomes just another piece of disposable PPE that requires frequent replacement.

Advances in Anti-fog Technology and Application
Today's advanced lens coating technologies actively manipulate moisture through surface acting agents, chemicals designed to move to the lens surface as needed to prevent fogging. The most reliable coatings employ dual-action properties:

  • hydrophilic properties that absorb moisture into the lens, and
  • hydrophobic properties that spread excess condensation in a clear film over the lens surface and ultimately shed moisture off the lens

Applying dual-action anti-fog coating so it goes on and stays on permanently, even after repeated washings and wiping, is key to the coating's durability. Look for manufacturers that bond anti-fog agents permanently to the lens and those that rely on controlled application methods and vigorous product monitoring that ensure anti-fog coatings absorb, then spread and shed, the greatest amount of moisture consistently over the longest possible time. A long-lasting, consistently fog-free safety lens is one your workers can wear shift after shift with the clear, fog-free view vital to performing their tasks.

Tips for Selecting Effective Anti-fog Eyewear

  • Look for anti-fog coatings that employ dynamic, dual-action (hydrophilic and hydrophobic) properties.
  • Be sure the manufacturer's batch creation and application processes are rigorously monitored and tested to ensure the highest standard of anti-fog consistency and longevity.
  • Be sure the application process delivers smooth, consistent results on every pair of eyewear to support distortion-free optics.
  • Look for manufacturers using an intense curing process to permanently adhere the coating to the lens. Only permanent coating will deliver consistent fog-free performance, even after frequent wear, wiping, and washings.
  • Look for anti-fog coating on a wide range of safety eyewear types, from goggles and sealed eyewear to spectacles, as well as lens tints, to provide anti-fog protection to workers across a wide variety of applications.

The need for effective anti-fog performance on safety lenses is clear. Look for proven technology that delivers the longest-lasting fog-free vision and durable staying power that stands up in the harshest, wettest conditions. By selecting effective anti-fog coatings on the styles and lens tints best suited for the application, workers benefit from uninterrupted vision and continuous protection from their safety eyewear. Employers benefit from a safe, productive, and compliant workforce, which supports a healthy bottom line.

1. Prevent Blindness America
2. U.S. Bureau of Labor Statistics
3. Prevent Blindness America
4. National Institute for Occupational Safety and Health
5. Prevent Blindness America

This article originally appeared in the August 2017 issue of Occupational Health & Safety.

OH&S Digital Edition

  • OHS Magazine Digital Edition - June 2020

    June 2020


      Recognizing and Mitigating Static Electricity Hazards
    • OIL & GAS
      New Gas Detection Technology
      Stop Sweating Heat Stress
      Electricity is Everywhere
    View This Issue