Why we see a object bigger or smaller?

Hi. Now I share you a simple knowledge of seeing ....
Do we know,  why we see a thing bigger or smaller?
Don't??  Let's know that...

We see a thing bigger or smaller for focus angle in our eyes.

Let me explain. 

Focus angle is the angle which is made by the refracted light rays of the object.

If the focus angle of object is big to our eyes,  we saw that big or bigger. On the other hand,  if the focus angle is small to our eyes, we see that small or smaller. 

Focus angle depends on distance between our eyes and the object.
Here have an formula,
          Focus angle =object size /distance

From the formula we can give,  if distance is bigger, the focus angle is smaller.  On the other hand, if the distance is smaller, the focus angle is bigger.

So,  if we give a object far from our eyes, we see that smaller. And, if we give a object close to our eyes, we see that bigger.

                      ""Thank You ""