MASKING

Okay, who is a photographer?  With the invention of the modern cell phone, everyone is. 

What would happen if you focus your camera on one item and then, while the lens is open, move it at a different item?   Answer:  you would get a blur.  Movement in a camera causes a picture to blur or streak. 

Now comes the question:  why doesn't this happen to our vision?  Our eyes are like cameras.  When your eyes move quickly from one object to another, you do not see these streaks or blurs.  "How come?" you ask.

Our rapid eye movement from one thing to another, for example when you are reading, is called saccade.  (pronounced sa-cod')  The reason you do not see the blur or streaks is called saccadic masking.  If everything is working as it should, your brain is doing this saccadic masking and it shuts off your vision for a femtosecond (or some such ridiculously short period of time) while you move your eyes from one object to another.  You don't even notice it.  [If you see streaks, see your doctor.]

One more time, we can be amazed by our brain and the One who made us.