Describe the reason why humans have a blind spot in their vision.
Humans have a blind spot because there is a hole in the retina called an optic disk, which is where the optic nerve fibers exit the eye. Humans are unable to see an image that falls within that area of the eye because it does not contain any rods or cones.
The human eye is structured in a way that it contains a spot on the retina known as the optic disc, where the optic nerve exits the eye and transmits visual information to the brain. This point lacks any light-sensitive receptors or cells and, as such, creates a gap in our visual perception, which is called the blind spot.
This anatomical feature is present in all vertebrates because of the way the eye develops from a structure known as the optic cup during embryonic development. Simply put, the optic cup comprises retinal cells that grow towards the optic nerve and connect to it. When the cells reach the optic nerve at the back of the eye, they form a hole that doesn’t contain any receptors, and that absence of these photoreceptor cells creates a gap in our vision.
However, we are not usually aware of this gap in our field of view because our brain fills in the missing information from our other eye and the surrounding area. Also, we instinctively move our eyes around to ensure the missing spot in one eye is complemented by the vision of the other.
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