This can be simply explained as the view you get of any object when it is seen with only one eye. It is not common for humans to experience this vision naturally as we use both of our eyes simultaneously to figure out any object. But when it comes to animals, many of them have monocular vision as their eyes are located on either side of their head.
In this way, they will have the ability to use each one of them separately. On the other hand, our eyes are positioned in the same direction and this gives a binocular vision. You can get a fair idea of what is monocular vision when you try closing one eye and see any object in front of your body.
You can later close the other eye and notice that the object moves slightly from your point of view. If you happen to touch the object while doing this, you may have difficulty in reaching the object exactly as the depth of the object is not well defined in this manner.
Do humans have monocular vision?
In rare cases, humans have such vision due to medical conditions. It can be by birth or developed at a later stage due to some injury to one of the eyes.
This condition is referred to as Monocular vision impairment and this will lead to a situation where the vision is proper on one eye and gets completely blocked in the other one. In such cases, the ability to perceive objects in three-dimension is difficult and the depth of view is also affected.
Apart from that, the balance is also slightly affected as the postural control of the brain gets affected due to monocular vision.
You have to understand the importance of having binocular vision and this is what gives us a fair idea about the distance of any object from our body. In this way, you will be able to walk and move freely without bumping into any objects on our way.
However, when you have vision in only one eye, it can affect the information perceived by the brain and this will impair the depth of view by a huge margin. You will not get complete information about what is present on the other side of the face which has blocked vision.
In this way, there are chances that people with such disorders will have issues with balance and they are more likely to have less postural control. You will be surprised to know that it can even happen to people who lose their vision due to cataract or any other issues.
When the vision is lost in one of the eyes, they will need some time to get used to seeing with only one eye and this will cause issues with postural control and balance.
What causes monocular vision in humans?
There are many reasons why people develop such impairments and this cannot be cured easily.
- It can happen due to birth defects when only one eye is functioning and the other one gets blocked completely
- Cataracts can cause this issue by clouding the lenses of one of the eyes
- The cornea gets obstructed due to some health issues
- Improper focusing of the light by the eyes can also lead to such issues
- Damage to the retina due to any injury or accident
Few animals have natural monocular vision
In that case, they will have their eyes positioned on either side of the face and this restricts their vision in some sense. They will not get the same image from both the eyes and they will be able to see a wide area unlike human beings.
This will help them in many ways as they need not have to turn their heads like us to get that wide view. It will help them to spot other animals approaching them from either side which will be useful when they have to survive in the wild.
However, they will have less depth of field and they will not be able to get the exact distance between the object and them leading to many issues. Many birds have monocular vision with the exception of owls.
Apart from that, few animals like goat, deer, cows and rabbits have monocular vision. If you notice carefully, you will observe that these prey animals actually benefit a lot from such vision as they get a wide field view.
This will help them to spot danger early from either direction which can help them survive in the wild.