I use one. Use it everyday.
It is the pureguardian blue or white light. Funny enough, I tend to use the blue light more, as it seems to be a little easier on my eyes. Purchased it on Amazon.
I also purchased the ugreen long arm adjustable clamp so I can put it to the height, distance and direction I want. I can also swing it out of the way when not in use. The light box clamps on upside down. It is actually meant for a phone or tablet. You do need the right desk to be able to attach the clamp to.

Another good one is one of the Carex ones that are height and angle adjustable without having an extra clamping device attached to your desk. This brand is often used in studies.

They work best being slightly above eye level to direct the light at a downward angle. Most sit on the desk pointing the light upwards, which isn't ideal.
As others have pointed out, have it positioned to one side as you don't look directly at the light.