WORKING OF THE EYE – EXPLAINED STEP BY STEP
A human eye is a unique organ in the body and has various unique parts and features within it. It is a muscle that works like a camera and provides vision. Let us first understand the structure of the eye before its working, to understand the process better.
The very front of the eye is called cornea. It is a transparent structure that helps to focus incoming light. Behind the cornea is a colored, ring-shaped membrane called the iris that can expand or contract to control the amount of light entering through the part called pupil.
Behind the Cornea is the pupil and behind the pupil is a lens which is colourless, transparent structure. It is known as the crystalline lens.
The space between the cornea and the iris is filled with a clear fluid called the aqueous humor. The retina, an optic nerve, is present at the backside of the eye where the images are formed.
The middle layer between the retina and sclera is called the choroid which contains blood vessels that supply the retina with nutrients and oxygen and also remove waste produced.
Let Us Now Understand Step By Step How The Vision Is Created
- First the light enters the eye from the front through the cornea
- After passing through the cornea, the light passes through the pupil. The pupil is surrounded by the iris which regulates the amount of light passing through the pupil.
- The light then strikes the lens of the eyes which focuses the light rays onto the retina at one point after passing through the vitreous humor
- The retina has various light sensitive cells called rods and cones. With the help of these cells, on the retina, an inverted image is formed and it carries the various light signals like color to the visual cortex of the brain.
- The brain then assembles the signals into images and provides vision.
The above process of forming an image happens for a normal eye with a normal vision. With a normal eye, a focused and sharp image is formed on the retina and hence the image formed or we see is clear.
Since eyes can have various issues, vision could be affected. Now with normal vision, the cornea and the lens focus light directly onto the retina but with some the light rays may enter the eye at different angles.
When this happens, the focus on one point on the retina is not made which causing blurred or distorted vision.