How We See – The Visual System Explained

You think you might know all there is to know about seeing…

except why things are sometimes blurry and the eye doctor wants you to wear glasses, contact lenses or have surgery to reverse the blur.

 

So, let’s SEE

Your eyes are attached to optic nerves that lead to your brain where what you see gets interpreted, so you understand what you are seeing.

http://www.dreamstime.com/royalty-free-stock-photos-human-eye-dissection-anatomy-isolated-white-background-d-render-image32002038Muscles on the top, bottom and either side of each eye move your eyes up and down and turn your eyes from side to side. These four muscles on each eye are called recti muscles and coordinate to move your eyes in all directions.

You also have a couple of muscles on the outside of each eyeball that wrap around like belts and these can squish your eye a bit to make it elongated – sort of like an egg – or, relax, so your eye reverts to its more natural round shape. These are called the oblique muscles.

When you look at something, light rays bounce off the object and enter your cornea: that shiny surface covering your eye. The iris is the colored part of your eye and surrounds the pupil, which is the black circle in the center. The pupil is actually an opening or tunnel that allows the light that enters the cornea to pass through the eyeball. Just behind the colored iris sits the lens – sort of a flexible bag of clear tissue that helps to direct the light on through the fluid of your eyeball and then on to the retina at the back of the eyeball where it is connected to the optic nerve that sends messages to your brain.

  • Light bounces off an object,
  • passes through your cornea
  • through the tunnel called the pupil
  • through the lens and
  • through the fluid of the eyeball
  • where it eventually hits the retina and
  • sends a signal to the brain via the optic nerve and
  • the brain interprets the signal.

Problems happen if the cornea is misshapen, as with astigmatism. That happens when there is uneven pulling of your eye muscles, which wrinkle the surface of the cornea. Blurry vision can also occur if your eyeball is held too tightly by the recti muscles, shortening the eyeball and creating far sightedness, or difficulty with reading and close up work. Similarly, if the oblique or belt-like muscles are too tight, then the eye ball becomes too long and then you have blurriness when looking off in the distance. When an eye is shaped incorrectly because of muscle tension, then the light that enters the eye converges at the wrong point which misses the retina and produces an image that is not distinct. With near sightedness, the light falls short of the retina. This is also called Myopia. In the case of far sightedness, the light converges behind the retina and this is also called Hyperopia if it happens in youth, or Presbyopia if it happens with advanced age.

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This converging of light is important to understand. The lights rays come into the eye and have to narrow down to a point to hit a very sensitive part of the retina to get the clearest image. This point is called the fovea centralis. When there is an irregularity in the shape of the cornea or in the shape of the eyeball, then the light doesn’t hit the sweet spot and a blurry image is produced.

 

Bear in mind that what you see, whether distinct or blurry, is subject to familiarity. This means that if you see something you have seen before, memory kicks in and assists you to recognize it. But if you see something for the very first time, then you will have to record memories in your brain by examining it thoroughly to add this new information to your memory files.

Natural vision therapy coaching helps you learn, or, re-learn, how to use all the parts of your eyes to see clearly and Reverse the Blur!