May 13th

Eye Physiology  ⁄  Function of Extraocular Muscles

When I observe a person with nearsightedness, he reminds me of the driver at the steering wheel of a supercar, waiting for the car to start going by itself wherever its owner wishes. When his desire is not executed, he thinks that his car is not like the others. In this article, I will tell you about our eyes’ capabilities, about the quick and exact actions they can perform. I hope, having read it, that you will feel respect for your eyes and that you will want to learn to operate them to release all their potential.

Extraocular muscles are cross-striated but are different than skeletal muscles. They consist of two types of fibers – extrafusal and intrafusal. Extrafusal fibers create the force that drives the movement and fixation of the eyes. Intrafusal fibers control the frequency of the pulsed discharge from the neuromuscular spindles (which sense muscle length).

There are two types of extrafusal fibers: fast phasic (80%) and slow tonic (20%). So eyes can make fast movements (saccade, microsaccade and tremor) and slow ones (smooth pursuit eye movement and drift).

Neuromuscular spindles are located near the muscle ends. Each extraocular muscle contains about 50 spindles. The spindles provide proprioceptive sensitivity (perceptibility) of the eye muscles. It is muscle feeling that helps us to do exercises.

The frequency of electric impulses in the eye muscles is much higher than in the skeletal muscles, reaching up to 200 impulses per second. This means that eye muscles are the fastest in the human body.

When tracking a slow-moving object (that is, when the angular speed of movement is not more than 60-80 degrees per second), the eyes make smooth pursuit movements. When tracking a faster object, the eyes make saccadic eye movements. Each saccade happens for 0.01-0.07 seconds.

During the fixation of the stationary object, our eyes are making three types of micromovement – tremor, microsaccade and drift.

Tremor is small trembling or vibration of the eye that has an amplitude up to 40 arcseconds with a frequency up to 150 movements per second.  Microsaccade is fast eye movement with an amplitude up to 50 arcminutes for 0.01-0.02 seconds. Drift is slow eye deviation, with an amplitude up to 30 arcminutes, which microsaccade breaks off to return eyesight focus to the object.

All these different eye movements provide the best visual perception of objects around us.

Some people may ask themselves, why do I need this information? How will it help me to improve my vision?

Speaking metaphorically, human eye is as complicated as an F-1 sports car. Imagine  an inexperienced driver at the steering wheel of the race car. It is clear that he will lose control of the car at the first turn. Surprisingly, the unlucky driver accuses the car of bad driving.

To use the eyes in the right way, you should fix visual objects correctly and control the visual processes. Using my techniques, it will take you 3-6 months of regular exercise to develop the correct visual skills. In the last article, I wrote about eye muscle warm-ups. If you tried to do this exercise, you may have noticed that your eyes move fast and it is as if  they run away from you easily. In the next lesson, I will tell you how to slow down these eye movements for better control.

Take care of your eyes. Get rid of myopia the natural way.

Dr. Arkadiy Davydov.

2 Responses

  1. Natalia:

    16.10.2016 at 18:57 #

    Hello Doc,
    I came across your site by accident and started reading your articles. I had a mild myopia (-1.5) but a year ago I read a book on neuroplasricity and dogged my glasses, tried doing exercises from Bates method, and also Feldenkrais. The best help I believe was the Feldenkrais, the awareness of straining and trying to relax the eyes before they got too tired. My current vision is -0.25. I also had reading glasses, for work (computer work 8 hours a day) and reading. I dogged those too, and now work or read without any glasses. Again, resting my eyes helps, and sometimes I need covering my dominant eye during work. But I believe I still have my bad habits. Wide vision that you describe rings very true for me. What is your theory on astigmatism? Is it just the product of the same bad habits, and could it be overcome with your exercises? My vision is often blurry, and the optometrist told me that while my myopia decreased the astigmatism increased. I refuse to wear glasses for astigmatism, and would rather work on correcting the bad habits. Please guide me what exercises to do and in what order. Thank you.

  2. Doc:

    17.10.2016 at 12:23 #

    Natalia, you should try the dynamic vision trainer to improve the right visual habits.

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