ELI5, Some LED headlights flicker when you don’t look directly at them, but when you do, it stops. Why?

47 views
0

ELI5, Some LED headlights flicker when you don’t look directly at them, but when you do, it stops. Why?

In: 8

Your eyes sense light with two types of cells: “rods” and “cones”. Cone cells are concentrated in the center of your visual field, and are responsible for color vision. Rod cells handle peripheral (off-center) vision, and are more sensitive to low light and motion. If you look off to the side (this is called “averted vision”) you can see the flicker because it’s mostly rod cells that are sensing the image.
This same effect is well known to astronomers and pilots – it’s often possible to see a faint star or distant aircraft at night by looking ever so slightly to the side of it.