When it comes to laser safety glasses, there is a wide range of colors and styles available, with varying degrees of lens darkness. The darkness of the lenses is determined by their Visible Light Transmission (VLT), which measures the percentage of visible light that passes through the lens. The higher the VLT, the lighter the lenses will be and the easier it will be to see through them. However, it’s important to note that not all lasers can be protected against with clear lenses.
Some lasers have visible beams, while others emit flashes or intense pulses of light that require darker lenses with lower VLT. The darkness of the lens helps to filter out the harmful wavelengths of light and protect the eyes from potential damage. Although it may be easier to work with clearer lenses, the safety of the eyes must always be the top priority.
At Phillips Safety, we offer a range of laser safety glasses with different levels of VLT, including clear lenses for low-power lasers and darker lenses for high-power lasers. It’s important to choose the appropriate laser safety glasses for the specific laser you are working with to ensure maximum protection for your eyes.
THE FACTORS THAT AFFECT VLT IN LASER SAFETY GLASSES
The visible light spectrum is the range of light wavelengths that are detectable by the human eye, spanning from approximately 400 nm to 700 nm and encompassing all the colors of the rainbow. Laser safety glasses are available in either clear or nearly clear lenses for lasers operating outside this spectrum.
However, for lasers operating within the visible light spectrum, some visible light must be blocked for safety, making it impossible for the lenses to be completely clear. The level of visible light transmission that is blocked by the lens is determined by the optical density, and the broader the coverage in the visible spectrum and the higher the optical density, the darker the lenses will be.
If your goal is to find laser safety glasses with the highest possible visible light transmission, you may want to consider glass filters as they generally have a higher VLT than plastic ones. The higher the VLT of your laser safety glasses, the easier it will be for you to see and work, but it’s important to note that some laser applications may require a specific VLT level for safety reasons according to OSHA. It is advisable to check with your Laser Safety Officer or the laser manual to determine if there are any VLT minimums for your laser or application.
THE IMPORTANCE OF PRIORITIZING SAFETY OVER VLT IN LASER SAFETY GLASSES
It’s worth noting that in some cases VLT may not be a significant factor, especially if the laser is not being moved during operation. If this is the case, you may be able to save money by choosing a filter with a lower VLT. However, safety should never be sacrificed for VLT. It is crucial to consider the requirements of your facility and to prioritize safety when purchasing laser safety glasses.
In summary, while high VLT laser safety glasses may be more desirable for ease of use, the safety requirements of your laser application should always come first. Be sure to consult with your LSO or laser manual to determine any necessary VLT minimums, and consider the safest and most appropriate options for your needs.