The nice thing about light is it's easy to see where the light is going. In my experience, the position of a bicycle to the right (US) of the travel lane makes the possibility of blinding on-coming traffic extremely remote. If the light is a spot light with a narrow beam spread, the light is more intense across the beam...see "lux" discussed above...but the spread from side to side is very narrow. There is little possibility of getting all that intensity across 12 to 20 feet of road to "blind" someone. If the beam is a flood, the lux is low but the spreading of the beam is wider. There is even less possibility of having enough intensity to "blind" someone.

"Blinding" light is also a rather strong term. Any motorist with even a small amount of night time driving experience has dealt with much brighter lights much closer to the driver and still been able to navigate. Even on darken roads and on-coming traffic running on high beams won't "blind" a driver. It might cause discomfort but it won't rob them of their sight.