I have a little, LED night-light. When it is on and the ceiling fan is on I can watch the blades as the LED strobes the blades. I’m assuming that it is strobing at 60 Hertz. I also have to assume that the strobing can harm the eyes but internal organs? Give me a break!
I put an adjustable LED above my shower, and when I turn it down low the hertz makes the water droplets look motionless and frozen in time, momentarily.