Last night a security guard in my Safeway parking lot shined his flashlight at my face as I sat in the car waiting for my wife. It actually caused pain in my good eye from mabout 50-60 feet away. I was a guard and used a high lumen light, too, for pitch black surroundings. This was in a lighted parking lot.

Watch how powerful your flashlight or bike light is in the high setting. Adequate is good. High lumens are bad, depending. Be considerate of victims when using the high setting like high beams on a car. Thats why you see very low lumen lights in Target and other stores. High lumens are to light things, not people's faces.

Distance of the light depends on lumens and size and depth of the refector. So, a low lumen flashlight with a big diameter deep refector can out distance one with high lumens and small reflector. Always look for distance ratings on the package, if power and distance are your forte. Look for battery saving technology.