Laser safety goggles and laser safety glasses are crucial to the safe and effective use of lasers.
Laser Safety Goggles: The What and the Why
Some facilities which run laser operations have a Laser Safety Officer (LSO) who is responsible for deciding which laser safety goggles to use. But other facilities do not use lasers enough to keep an LSO on staff. This article will help the latter (and quite possibly the former) to make more informed decisions about laser protective eyewear.
Laser safety goggles have lenses that absorb, attenuate, or reflect specific wavelengths of light at specific strengths (optical densities). This protects the sensitive photoreceptors of the eyes from being damaged or destroyed by direct or scattered laser radiation.
Here are some things that are useful to know about laser safety goggles:
- Laser safety goggles have lenses that are specified to protect from certain wavelengths of light. These specifications are noted on the glasses, often in ranges (i.e., 200-300nm) and always with a specific optical density specified (i.e., 5+ OD).
- The wavelength of light is measured in nanometers (nm). Your laser will operate at a specific wavelength or range of wavelengths of light.
- The lenses for laser safety goggles are often called laser filters because they filter light.
- Just because a laser’s beam is not visible does not mean that it is incapable of injuring or destroying skin or an eye. Many laser safety filters protect from invisible laser radiation.
- The optical density (OD) of a laser filter denotes how much the filter blocks light at a specific wavelength. The higher the OD, the less light gets through at that wavelength.
- Some filters are darker than others, but that does not necessarily mean that they block more. Protection from lasers occurs in the visible light spectrum (roughly 400-700nm) and well outside the visible spectrum (200-400nm; 700-5000nm). Lenses that appear to be dark just happen to block more light in the visible spectrum than lenses that seem clearer.
- Visible light transmission (VLT) is the amount of visible light that passes through the lens. This only deals with visible light and is marked as a percentage.
- Laser filters in laser safety goggles generally come in either glass or a type of plastic material. Glass generally has higher VLT than plastic, whereas plastic lenses are thinner, lighter, and easier to produce with new coverage. There are a number of reason why one might desire a glass laser safety lenses over plastic safety lenses, and vice versa.
It is easy to become confused by laser goggles if you are not used to all of the terminology associated with laser safety. If you are ordering laser safety goggles from a company, it is a good idea to ask them any questions you may have. It is certainly a good idea to be absolutely certain you know that you’re getting the right laser safety goggles before you order them. If you make a mistake with laser safety, it could be the difference between keeping or losing your vision.
If you’d like more information on laser safety goggles, take a look at our other articles, and thanks for reading!