Question: when you stare at a bright light and look away, you see some discolouration. are there any long term effects for this?

Stephen Moss answered on 15 Mar 2011:

@bouncingball8
When we look at something bright we bleach the molecules in our eyes that detect light, which is partly why you see strange colours when you then close your eyes or look away. However, those molecules are being made at the rate of billions per second, so they are quickly replaced. This means there are no long term effects. However, look too long at something too bright, and you’ll do more than just bleach a few molecules, you can actually kill the light-detecting cells, which if severe can cause blindness. This is why we’re always told never to look directly at the sun.