Why do dim sources of light seem to disappear when you look directly at them?

Question

For example a dim light coming from underneath a door – I can see there’s light when I look to the side of the door, but when I look at the gap at the bottom of the door it seems to be pitch black

In: Biology

Answer 1

The centre of the retina of your eye has light receptors called cone cells that are good for colour and fine detail but aren’t as sensitive as the rod cells away from the centre.