What Parameters Should You Consider When Using Laser Safety Glasses?

Laser safety glasses are essential to protect our eyes from harmful laser radiation during operations such as laser cutting, welding, engraving, and medical or laboratory use. However, not all laser safety glasses are the same. Choosing the right laser safety glasses requires understanding several key parameters to ensure effective protection and compliance with safety standards. In this article, we will explore the most important parameters to consider when using laser safety glasses.

1. Wavelength

Wavelength is one of the most basic parameters to consider when choosing laser safety glasses. Lasers emit light of specific wavelengths, and different wavelengths have different effects on the eyes. For example:

Ultraviolet lasers: 190–400 nm, which usually cause damage to the cornea and lens

Visible light lasers: 400–780 nm, which will directly penetrate the human eye lens to damage the retina and even the optic nerve, causing irreversible damage.

Near-infrared lasers: 780–1400 nm, which will directly penetrate the human eye lens to damage the retina and even the optic nerve, causing irreversible damage.

Mid- and far-infrared lasers: 1400–11000 nm, are similar to UV lasers in terms of their damage to the human eye, primarily to the cornea and lens.

Laser safety glasses are designed to block or attenuate lasers in a specific wavelength range. It is critical to ensure that the wavelength range covered by the glasses matches the wavelength of the laser being used. If the glasses do not cover the relevant wavelength, they will not provide adequate protection, exposing the eyes to potential damage.

2. Optical Density (OD)

Optical density (OD) measures the amount of light blocked by laser safety glasses at a specific wavelength. The higher the OD value, the better the protection.

For example: OD 6 blocks 99.9999% of laser energy at a specified wavelength.

Tip: Choose laser glasses with an OD value that matches or exceeds the laser power and wavelength you are using.

3. Visible Light Transmittance (VLT)

The primary function of laser safety glasses is to block harmful lasers, but they should also allow enough visible light to pass through to ensure a clear field of vision. Visible light transmittance (VLT) is the percentage of visible light that passes through the glasses.

The higher the VLT, the better the visibility, but the laser protection may be worse.

The lower the VLT, the better the protection, but it may affect the view of the surrounding environment.

The right laser safety glasses can be selected according to the specific working environment and needs.

4. Certification and standards compliance

Check whether the glasses meet the following international safety standards:

ANSI Z136.1 (US)

EN 207 / EN 208 (Europe)

CE Mark (EU)

Certified glasses ensure that the product has been tested and rated for laser protection.

5. Materials and comfort

Comfort is important for long-term use:

Lens material: polycarbonate, glass or special filters

Frame size: adjustable straps, foam padding or all-inclusive design

Weight: lightweight materials help reduce fatigue

Comfortable glasses facilitate continuous use and reduce the risk of accidental exposure.

6. Laser Types and Applications

Different lasers (e.g. CO₂, Nd:YAG, diode, fiber) emit lasers at different wavelengths and intensities. Please determine the type of laser you are using to select the appropriate glasses.

Medical lasers: laser safety glasses with relatively high light transmittance are usually required

Industrial lasers: laser safety glasses with high or even higher light density may be required

Research lasers: multi-wavelength protection may be required

Conclusion

Choosing the right laser safety glasses is more than just choosing any tinted glasses. Critical parameters such as wavelength, light density, and certification ensure effective protection for our eyes. The right laser safety glasses must be selected according to the specifications of the laser equipment we are actually using to minimize risks and ensure safety in any environment.