Most laser hair reduction devices target pigment/color. The pigmented hairs/follicles absorb the light (because of their pigment), can't tolerate the energy, and the follicle dies. Blonde or brown hair is almost pigment-less and therefor can't absorb the light from the laser. Unfortunately, this is true of most laser hair devices. I would consider electrolysis.
At this time the LightSheer doesn't work for light hair color. It only attracts to the darker pigmented hairs.