Buyers Guide | Visible Light Transmission ("VLT") in Relations to Laser Safety Glasses
Most eyewear offer specific wavelength protection enabling others wavelengths along the visible light spectrum to be transmitted permitting the optical viewing conditions. The higher the visible light transmission, the more color is getting through the lens. An example is distortion when wearing sunglasses to block the sun, (often less expensive) sun glasses do an effective job of blocking the sun, however everything is much more difficult to see because not a lot of light generally is coming through. Other times with (typically more expensive) sunglasses, the sun is blocked and everything else looks very similar to how it would without the glasses.
If seeing the greatest possible visible light is important while protecting yourself from lasers, it may be best to pay more for the dielectric coated glasses over the polycarbonates as they have a higher VLT relative to the amount of wavelengths they protect from.
Visible Light Transmission is an average of visible light transmission over the whole visible spectrum. It is important to note that diversity of the visible light being let through can also be a factor when looking for glasses and goggles. Below is a simplified image of what high visible light transmission and low visible light transmission look like.
|High Visible Light Transmissions||Low Visible Light Transmissions|