how can brain determine near or distant objects?
i mean when we look at near object our eyes lenses adapted to that distance but when we look at distant object that lenses must adapted to new situation. how our eyes realize the object is near or distant then adapt it self to new situation?

Question

how can brain determine near or distant objects?
i mean when we look at near object our eyes lenses adapted to that distance but when we look at distant object that lenses must adapted to new situation. how our eyes realize the object is near or distant then adapt it self to new situation?

abb0t · Answer

Is it not because we have binocular vision?

anonymous · Answer

what do you think @ganeshie8 , @aaronq ?

anonymous · Answer

can you explain more @abb0t ?

abb0t · Answer

I think it's because of our retina produces slightly different images and the difference in images is a direct result of the depth of the objects that we are looking at.
Close one eye and you'll see much closer to see this.

But, when we see with both eyes what we see is assembled in the brain and they are interpreted as depth.

anonymous · Answer

i don't talk about eyes that have problems.assumed that eye is normal.

anonymous · Answer

do you understand my question or not?

anonymous · Answer

what do you think @KlOwNlOvE , @Opcode ?

opcode · Answer

Put you finger in front of your face, close one eye and open the other, do it again.
Notice how the finger moves, this is because your brain now has more information of the surrounding area and can now add in those details.

There are three known methods of perceiving depth:
Oculomotor: Lets us determine depth by, our eye position and tension. 
Monocular: Vision with one eye.
Binocular: Vision with two eyes, that the brain assembles together.

Generally we award perceiving depth to 'binocular disparity'. Binocular disparity is a combined image from different viewpoints. (Two viewpoints hence binocular.)

Our eyes are around 6cm spaced apart, thanks to this we receive two viewpoints in our brain, and our brain merge the viewpoints together allowing us to see one image. However since we combined two viewpoints we also get depth information. 

Although thanks to binocular disparity visual illusions are frequent. Next time try closing one of your eyes when you see one, there is a good probability that the visual illusion will stop if it depends on binocular disparity. 

Source:
What @abb0t said, but just to elucidate.

Peace.