The Eye as a camera
God has blessed us with two eyes. Each eye is sort of a camera used for taking pictures. Like a camera, they too have a diaphragm, that is adjusted as per the intensity of the light entering. This Diaphragm is that the 'iris' of the eye, which gives the eye its color ( like Brown, Blue, Green, or the other combination).The eyes even have a system that allows us to visualize things at a far or short range. This consists of a 'lens', which can amend or alter its form to bring objects at completely different distances into focus.
Working as an ideal camera, the eyes have a 'control center' to regulate eye movements and therefore the size of the pupil (the black dot within the center of the Iris) through which the light is admitted to the eye. This control center is found within the brain. It is automatic, so unconscious.
But the images are received on the retina (The light-sensitive film at the back of the eye) have to be compelled to be analyzed, processed, and interpreted. This is carried out in a part of the brain with our conscious activity: The Grey cortex of the Cerebral Hemisphere, at the back of the head. The eye is designed to bring light rays to focus at the retina. Whereas the cornea (Transparent surface of the eyeball) does most of the focusing.
Merging of Images into one
Similarly, the images sent by two right-hand halves of the Retinas merge in the right-hand part. The occipital zone (back of the head) of each hemisphere receives an image that is a mixture of two half pictures, and it is here the whole merging of the messages received by the retinas is carried out.
Why two eyes?
The Purpose of the two images by two eyes is to give Three-Dimensional Vision. The Pupils the opening within the Iris is about 6 cm (i.e. 2 ½ inches) apart. Each eye sees an object from a slightly different angle. This spacing between there two sight centers enables us to visualize things in relief.
Source: Wisdom by Dr. K.V. Govinda Rao, Encyclopedia, Pinterest, Wikipedia