Anti-fog: What It Is and How It Works

There’s nothing worse than a fogged-up lens ruining a perfect day of freeriding in the woods or enjoying a ride on the slopes. This common problem for outdoor sports enthusiasts can not only hinder enjoyment but also compromise safety. Fortunately, significant advancements have been made in lens technology over the years. From single-lens goggles, we’ve moved to double-lens systems that compensate for thermal shock between facial heat and the cold outside air, and the use of anti-fog treatments has become standard. However, it’s essential to know that not all anti-fog lenses are created equal!

What Is Anti-fog Treatment?
Anti-fog is a hydrophilic material layer uniformly applied to the inner surface of snow goggles, protective eyewear, and other optical devices. This layer absorbs moisture, reduces the surface tension of water droplets, and spreads them evenly across the lens. This prevents the formation of annoying condensation that impairs visibility.

The concept is simple yet effective: the hydrophilic material attracts water, eliminating the phenomenon of isolated droplets that occur under conditions of high humidity or temperature fluctuations. This is especially helpful in sports where the body generates heat that interacts with the cold external environment, creating a “perfect storm” for lens fogging.

Not All Anti-fog Treatments Are Equal
It’s crucial to understand that there are specific standards for defining the quality of an anti-fog treatment. For example, the EN166 standard stipulates that, to be classified as anti-fog, a lens must resist fogging for at least 8 seconds during a standardized test.

This means that the term “anti-fog” isn’t just a generic label—it’s backed by measurable parameters indicating the treatment’s effectiveness. However, many manufacturers don’t explicitly disclose these performance metrics, leaving consumers without clear tools to compare products.

How Is Performance Measured?
The duration of fog resistance during the anti-fog test is the main indicator of quality. The longer a lens resists fogging, the better the treatment applied. To give you an idea of the differences between available treatments, our brand uses a special formulation that allows lenses to resist the test for over 300 seconds. That’s more than 37 times the minimum requirement set by the EN166 standard.

What Makes a High-Quality Anti-fog Treatment?
Superior performance doesn’t just stem from the formulation of the hydrophilic material but also from the quality of its application. A uniform coating is essential to ensure that moisture is effectively managed across the entire lens surface. Moreover, advanced treatments are often more durable and resistant to wear, providing consistent performance even after many uses.

Interestingly, our treatment exceeds the maximum measurable limit of the standard test. The testing machine is programmed to stop after 300 seconds, meaning we don’t know the true upper limit of our anti-fog performance—it might be even better!