Why can we still see lasers after wearing laser-protective goggles?

Laser-protective goggles are designed to block or attenuate the specific wavelength of the laser that they are intended to protect against. However, no laser protective goggles are 100% effective at blocking all of the light that enters them.

When you look at a laser through laser-protective goggles, some of the light from the laser may still pass through the goggles and reach your eyes, albeit at a reduced intensity. This reduced intensity may not be harmful to your eyes, but it may still be visible.

Additionally, the goggles themselves may scatter some of the light that enters them, causing some of the light to reach your eyes from directions other than the direct line of sight to the laser. This scattered light may also be visible.

It's worth noting that even if you can see the laser through laser-protective goggles, this does not mean that the goggles are not effective at protecting your eyes. As long as the goggles are designed to block or attenuate the specific wavelength of the laser you are working with, they should still be providing some degree of protection. However, it's always best to exercise caution when working with lasers and to follow all recommended safety procedures.