Binocular and stereo vision
We all have two eyes? Are they really necessary? Can we
not do with just one?
Each eye looks at an object and draws information about
it. Because the eyes are not in the same position, each
eye has a slightly different view, the net effect being
that while both the eyes see almost the same, each eye sees
a little bit extra. The brain matches the similarities in
both the views, adds the extras from both eyes to get the
impression of the object. Thus vision from both eyes or
binocular vision is when both eyes work together to draw
information about an object. The effect of this is very
important. Binocular vision results in stereovision, which
enables one to see and perceive three-dimensional objects.
This provides depth perception and an ability to visually
judge relative distances between objects.
To understand how the brain interprets the information obtained
from the two eyes, try to focus each eye on a different
object. For example, roll up a tube of paper and look through
it with one eye. Place your open hand against the middle
of the tube and look at it with the other eye. You will
see your hand with a hole in it, for, the brain is receiving
two very different images and putting them together.
A good binocular vision has the following abilities:
These abilities are very important. Simple tests can be conducted to test binocular vision and an early examination can help rectify vision impairments.