The rods in the eye are responsible for our "night vision". They see in shades of gray only and are most sensitive to the frequency (wavelength) of light we call "cyan". However they cannot see the color, only the intensity. In order to use cyan and preserve your night adaptation, the lowest possible light level must be used. At the light levels required to preserve your night adaptation you actually cannot (and better not!) see the color of the light reflecting off the subject, but only detect it as "light". In this circumstance you are actually using your "night vision" to see with, but you need exceptionally little light for this to work. Increase the light levels and the chemicals in the rods break down and you lose your dark adaptation and the blue cones kick in and allow you to perceive the light as "cyan".
Red is best for times when you need greater levels of light but need to preserve your night vision. The red cones will pick up the red light but the rods will not. The rods are essentially blind to red light. Once the red is shut off the rods can immediately go back to what they were doing at the same level of night adaptation they were at when you turned on the red light.
So cyan is best at exceptionally low light levels since this light is what the rods pick up best (but you better not be able to see it as "cyan"), while red is best at preserving that precious night vision when you need brighter light to navigate and see details.
Therefore, this uberbright cyan headlamp is actually the absolute worst possible thing to use if you are trying to preserve your night vision. It will immediately blow out the rods' night adaptation since cyan light is what they are most sensitive to. You may as well make it a white light and enjoy full spectrum vision.