Child Health A-Z

Normal Vision

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What is normal vision?

In order to better understand how certain problems can affect your child's vision, it is important to understand how normal vision occurs. For children with normal vision, the following sequence takes place:

Light enters the eye through the cornea, the clear, dome-shaped surface that covers the front of the eye.
From the cornea, the light passes through the pupil. The iris, or the colored part of your eye, regulates the amount of light passing through.
From there, it then hits the lens, the transparent structure inside the eye that focuses light rays onto the retina.
Next, it passes through the vitreous humor, the clear, jelly-like substance that fills the center of the eye and helps to keep the eye round in shape.
Finally, the light reaches the retina, the light-sensitive nerve layer that lines the back of the eye, where the image appears inverted.
The optic nerve is then responsible for carrying the signals to the area of the brain (the visual cortex) which assembles the signals into images (i.e., our vision).

Last Update
February 3, 2008

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