If you own one of those Chinese 1 to 3 led bicycle lights. you can add a diffuser lens to have a cutoff beam. Need to measure the diameter to be sure the lens fits before ordering.

https://www.amazon.com/gp/aw/d/B00RKP6GZG/ref=mp_s_a_1_1?ie=UTF8&qid=1475641326&sr=8-1&pi=SY200_QL40&keywords=bicycle+light+lens&dpPl=1&dpID=51iiL4DiA5L&ref=plSrch

It's a cheaper way to have a bright front light w/o blinding oncoming traffic or pedestrians. But with the diffuser/cutoff lens, you get a wider beam and lose a few lumens of light. Everything depends on your main night riding conditions, road/street or mtn/trail/unlit country roads. "Most" current front lights have the classic flashlight/torch light pattern/adjustments, so controlling that light can be problematic if you have to constantly adjust the beam up or down and/or zooming in or out.

Some mount 2 front lights, one with a cutoff beam (low beam) and turn on the other (high beam) if they want to see things above the horizon...tree branches, etc.