Post: The Science Behind Dark Laser Safety Goggles and Why They Are Necessary

The Science Behind Dark Laser Safety Goggles and Why They Are Necessary

If you work with lasers, you are probably familiar with the importance of wearing laser safety glasses. However, you may find yourself questioning why some glasses are very dark while others with coverage over more wavelengths are clear. The answer lies in the concept of visible light transmission (VLT).

Visible light transmission refers to the amount of light that can pass through the lens, with higher VLT allowing more color to pass through. The purpose of laser safety glasses is to block specific wavelengths of light while allowing the rest of the light to filter through specially designed lenses. This allows individuals to work safely without being obstructed by darkness or hazardous laser beams.


Laser safety goggles are capable of covering a wide range of wavelengths of light, spanning from 100 to 15,000 nanometers. Interestingly, the visible light spectrum only occupies a small portion of this range, approximately between 400 and 700 nanometers. As a result, coverage outside of the 400-700 nm range will not impact your vision, since it blocks light that falls beyond the visible range, including ultraviolet and infrared light.

The danger of a laser doesn’t always correspond to its operating wavelength, as various lasers can function at different wavelengths. In cases where there is a laser operating at a wavelength in the visible spectrum, you require laser safety glasses that are not clear and may appear dark, as they provide necessary protection within the visible spectrum.

Furthermore, for those working with lasers in the visible spectrum and requiring high optical density coverage, darker lenses are necessary compared to those who only require lower optical density coverage (3 or below). Lower optical density lenses allow more light to pass through the lens. Therefore, if you are working with a laser that has the potential to harm your eyes, you need a higher optical density coverage which requires darker lenses.


The material of the lenses can greatly impact the darkness of laser safety goggles. If you opt for a plastic material, such as polycarbonate or acrylic, chances are your lenses will be quite dark due to the nature of plastic laser lenses.

If visible light transmission is a crucial factor in your laser work, you may want to consider choosing glass laser lenses instead. Glass typically has a higher VLT than plastic, which means the lenses will be lighter in color and allow more visible light to pass through.

While some lasers require darker lenses, others operate outside of the visible light spectrum, making it simple to find lenses with higher VLT. Certain lasers, however, fall somewhere in the middle of these two extremes. If you require a laser safety goggle with a high VLT for such lasers, it is advisable to contact Phillips Safety to explore options for getting the highest VLT possible for your specific laser application.

In conclusion, laser safety goggles come in different shades of darkness depending on the laser type and the required level of protection. It is important to consider the visible light transmission when choosing laser safety goggles for your laser application. Whether you need high or low VLT, Phillips Safety has the best options for you, ensuring the right level of protection for your eyes.

If you still aren’t sure which laser safety glasses are right for you, it’s a good idea to give us a call at 1-866-575-1307 or talk to us through our chat or e-mail us at

Our experts will be able to tell you what you need for your application.


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