For those that have peep holes in their homes or apartments to look and see who is at the door can they see you?

I don't think they can see what you do, but sometimes when you look through the peephole the change of light might make them notice that you're looking.

We don't have peepholes in our doors, and I am too lazy to look up the correct answer right now, so I will just guess. :P Hahaha. I could be wrong, but I have this idea that peepholes have covers on them that the person inside the door moves aside in order to look into it. If so, then the person outside, would not be able to look from the outside when this cover is in place. Whether he can see inside if the cover is removed, I do not know. But I expect it can be startling if you are inside, someone knocked, you looked through the peephole, and see an eye looking in.

The one who is outside cannot properly judge if someone is watching him from peep hole?

They might notice that someone is looking but not see us. Our door doesn't have a peephole but I will get a camera instead.

Surely they would be able to see your eye and know that you were looking at them.

I don't really know. I thought you could but it doesn't seem sensible to be able to do this.

Well people can`t see you of course but they can feel your footsteps coming from your peep holes

my flat needs visitors to get through the downstairs front door before reaching my uptair home too which is quite a secure system

When I lived in NYC we had a peep hole in mom's apartment door. If the hallway was dark and I pushed the flap aside to look out at who was there it was a possibility that they could see a glimmer of light coming from the peep hole so that was not good. Otherwise they could not see me looking. However in that apartment building they put in a system intercom downstairs so we didn't even have to let anyone up if we didn't want to or didn't know them.