Q: What is beam angle and why does it matter?

Some LED light panel manufacturers use a wide beam angle of 90 degrees. The problem with using a very wide beam angle is that the power density drops quickly over distance. The angle that light comes out of a light source is the main factor in determining how the power density drops over distance. Wide beam angles (90 degrees) make the power density weaken very soon. If you are planning to use the light for a larger area (and therefore plan on sitting / standing back further from the device), a 90 degree beam angle typically is not the best choice.

Conversely, other light panel manufacturers may use a very narrow beam angle of 30 degrees. This design choice often necessitates the LEDs being packed closer together to avoid dead spots. This may mean higher 'peak' power measurements for the lights, but the devices tend to be physically smaller (due to the LEDs needing to be closer together).  Anectodical experience with 30 degree beam angle devices is that they can be uncomfortable to even briefly glance at. We consider 30 degree beam angle devices to be generally less safe and less user friendly than wider beam angle devices. 

The Mito Red Light Panels use a 'sweet spot' beam angle of 60 degrees to ensure therapeutic power density at further distances, while maximizing for usability, comfort and safety.