by Leo Anghart
Dr. William Bates maintained that if you practice reading small print regularly then you will also maintain your natural clear eyesight. When you are able to read really small print then you are using your central foveal vision perfectly and it is impossible to strain your eyes doing that.
Here is the same paragraph this time printed in 3-point letters.
Dr. William Bates maintained that if you practice reading small print regularly then you will also maintain your natural clear eyesight. When you are able to read really small print then you are using your central foveal vision perfectly and it is impossible to strain your eyes doing that.
Read it in good daylight. What does it feel like to read this small print? How close-up can you read it clearly?
Practice reading as close as possible to your eyes. The normal near point of clear vision should be about 15 cm from your eyes. Move your reading material back and forth so your eyes begin to refocus at a closer and closer distance. With this simple trombone movement you are actually exercising your ability to read close-up.
You will notice an improvement almost right away. Keep doing the exercises until it becomes very easy for you to focus close-up and read comfortably for extended periods of time. After that, practice some of the exercises once in a while to keep your near focusing ability in top form.
19. Convergence
The eyes of people with good vision naturally point to and converge at the object of interest. That is, the eyes rotate slightly so that the central fovea, where vision is clearest, is pointed directly at what you are looking at. The medical term for this is vergence function. You have probably noticed how the eyes turn inward when someone is looking at something very close-up, for instance when threading a needle. The eyes automatically turn in to keep the needle and thread in sharp focus. On the other hand, when someone is looking at a landscape the eyes seem to point almost straight ahead. Your eyes have this marvelous ability to always keep anything you want to see in sharp focus. Your eyes can watch a skier rushing down a mountainside and still keep the figure in focus while the background rushes by.
With proper convergence you have depth perception and experience the world in 3D. The brain automatically fuses the image from your left and right eye together into three-dimensional perception. You instantly know where things are located. Good depth perception is very important if you play ballgames where you need to catch a ball. If your convergence is off, you tend to misjudge where the ball will fall. Either you attempt to catch it short or the ball will fly over your head. Lack of convergence, or stereovision, usually does not affect reading. People with mono-vision using only one eye generally develop alternate ways of approximating distance, for example, by judging the size of objects.
It is believed that stereoscopic vision is developed by the age of 4 months and will be fully established around 8 years of age. Generally it is assumed that the entire visual system is fully developed by this age.
Severe convergence problems develop when one of the eyes turns in, as in esotropia or when one of the eyes turn out, as is the case in exotropia. This condition is known as strabismus. When the image from one eye crosses the midline of the retina, this operates as a trigger and the brain suspends the image from that eye in order to avoid double vision or diplopia.
To illustrate this phenomenon, look at something at a distance. Now, put your index finger in between yourself and the object. How many fingers do you see? Look at your finger – what happens to the object you were looking at? When you look at something in the distance anything in between will seem to double because the eyes are converged towards (pointing to) a more distant object. The foreground will be slightly out of focus.
Natural convergence can slowly drift out of alignment. This happens very slowly and you probably will not notice this until you get your eyes tested. Convergence issues often play a role in vision problems. If your eyes are always converging slightly in front of what you actually want to see, then your eyes are over-converged and your vision will be out of focus – especially in low light. In environments where your pupils are opened widely, your depth of field will be very shallow. In bright light your pupils will be very small and your depth of field will be very large, resulting in a sharper image. The world will appear much clearer on a bright summer day.
Vision Training principles for convergence
• Practice the string exercise on page 124 which is designed to provide feedback as to when you have convergence.
• Practice moving the convergence to the point of attention. This is to correct for convergence ahead or behind the object you are looking at.
• Check that you have convergence at both near and far viewing distance.
From a Vision Training point of view convergence is quite easy to correct using a piece of string as a feedback device. We use an optical illusion that takes place when you are looking down a string with both of your eyes open. If you have perfect convergence you will see a phantom cross with its center right at the object you are looking at. The center of the cross will be where you focused your attention on the string.
How to test for convergence
Fusion is one of the easiest things to check and correct. Take a piece of string, about the length from hand to hand stretched across your chest (about 1.25 meters). Tie the string to the back of a chair or to a door handle. Next you will need a paperclip or a bead, which you can move up and down the string.
1. Place the loose end of the string on the tip of your nose so the string is stretched out.
2. Place the paperclip on the string somewhere in the middle.
3. When you look at the paperclip you should see two phantom lines crossing directly through the paperclip. If you see the cross in front of the paperclip then your eyes are under-converging. If you see the cross beyond the paperclip then your eyes are over-converging. If you see only one string, then one eye is suppressing the image. The brain is only attending to one image and is blocking the affected eye – you are only using one eye. Any misalignment contributes to your vision problem and makes images blurry.
In some cases the outer eye muscles are too tight and refuse to allow the eyes to move in. If this is the case, then practice looking at your finger while you move it in from arm’s length to physically touching the tip of your nose. When looking at something up-close, your eyes move in towards the nose.
Aligning your fusion point is easy. Simply move the paperclip in or out until it coincides with the cross point of the “X.” In some cases people see a “V,” others perceive it as more like an “A” and some people see the phenomenon more like a “Y.” Any of these are fine as long as the convergence point is directly through the paperclip. When the paperclip is located at your fusion point, begin to move it back and forth while holding the fusion point through the paperclip. If you move the clip slowly, your brain will begin to align your eyes so they point directly to what you want to see. This is a recalibration and your brain will begin to automatically fuse your vision perfectly.
Possible patterns you might see. Make sure that the center point is right through the paper cip.
All the mind needs is a reference and it will automatically make the adjustments for you. Do this exercise for a few minutes only, but do it about ten times a day until you can easily place the center of the cross anywhere on the string. Look away and look back and still find the cross through the paperclip. Then you have completed the exercise and have perfect convergence. In my experience, which tallies with the findings, this adjustment takes place quite rapidly and is highly effective. Research suggests more than 85 percent efficacy.
Convergence and reading
I often come across people with presbyopia (the need for reading glasses) where convergence is a big part of the problem. For one reason or another, the eyes develop difficulty in turning inward. The outer eye muscle is held too tight. Perhaps it is because their mothers told them not to cross their eyes as a child. In fact, for proper reading your eyes need to
turn in (converge) a few degrees. If not, your near point of clear vision will drift further and further away and you will develop presbyopia.
Convergence can be corrected optically with prism elements. A prism bends the light towards the base of the prism and thereby corrects for the divergence. The disadvantage of prism therapy is that they quickly become very heavy. Also there are limitations to the range of vision divergence a prism can compensate for. Prisms are mostly used for treating strabismus. Of course, the prism will do nothing for the underlying convergence problem.
Convergence practice exercise
This exercise is designed for developing perfect convergence. Take a string and measure off 2 meters. Next, tie knots every 10 cm along the string. To make the knots stand out you can paint them with colored markers. Alternatively you can tie on colourful beads or small plastic rings. Colored paperclips would also do.
To perform the exercise, tie one end of the string to a door handle or to the back of a chair. Take the free end of the string and put it on the tip of your nose. Keep the string straight and look down its length. You will see a cross centered over every knot you look at. Move your attention from knot to knot and notice how the cross keeps jumping. Vary the exercise, looking at every second knot, every third knot and so on. Also, look away and find the cross again instantly. Develop the ability to see the cross when you look up, down and to the side. Do this exercise about five times a day until you can do it effortlessly; then you will have perfect convergence.
20. Strabismus
Strabismus is a condition where one eye is turned in a different direction from the eye that is used for seeing. The divergence can be towards the center and is then called esotropia (from the Greek ese meaning inward). The inner recti muscle is too tense causing the eye to be turned too far inward. This accounts for almost 50 percent of all cases. When the eye turns out it is known as exotropia (from the Greek exo meaning outward). The divergence may be only slight and almost imperceptible to very severe, in which case the pupil is almost hidden in the corner of the eye. The divergence may also occur upwards and is then called hyperphoria (from the Greek hyper meaning above) or it can be downwards and is then referred to as hypophoria (from the Greek hypo meaning down). Strabismus is usually present at a very early age but can also develop in adults.
Because of the divergent stressful double vision that is experienced, the brain switches off the image from the divergent eye creating amblyopia (or lazy eye). This is the reason strabismus and amblyopia are associated.
There is also a type of strabismus known as heterophoria, which is a deviation that is held in check by normal convergence. In some people you might notice a slight divergence, especially when they are engaged in internal processing. However, when they focus on you or some object of interest the eyes are perfectly co-ordinated.
The cause of strabismus is not known at the present time. The usual approach is to first treat amblyopia if it is present. Strabismus itself may be treated by inserting prisms into the glasses in order to correct for the divergence. However, there is a limit to how much divergence can be treated (up to 5D prism diopters) before the glasses become too heavy. Fresnel lenses are sometimes used since they are lighter and can be constructed to correct a higher degree of divergence.
Correcting the divergence with optics does very little to address the underlying causes. The angle of the prism shifts the image position so the brain perceives it to be within the range of convergence. But the moment you remove the prism you still have strabismus.
Surgery is another option that is often recommended by ophthalmologists since it corrects the eye position so the cosmetic appearance is improved. However, the vision is not always improved when surgically shortening or repositioning the eye muscle. In any case, surgery should only be contemplated after all other options have been exhausted.
Ophthalmologist William H. Bates (1920) concluded that strabismus was caused not by the strength of the muscles but by strain. In that respect he felt there was no difference between near-sight, far-sight and astigmatism. They were all functional problems that respond to Vision Training.
Strabismus is usually a condition that afflicts children. However, it is not unheard of in adults. In many cases the individual has been to see a profusion of doctors at various clinics. Often the traditional treatment procedures lead nowhere and only build more frustration for all concerned.
In my experience children respond very quickly to Vision Training and are greatly relieved when they don’t have to wear eye-patches and undergo other uncomfortable treatments. One case involved a 9-year-old girl who had been to a number of eye doctors. She was wearing bifocal glasses at the time I saw her. Her distant vision was quite good but her problem was seeing medium and near objects. The doctors recommended surgery but the parents were reluctant to subject their daughter to this, especially when they realized that the chance of success was not very high.
First I taught her the butterfly exercise (see below), which is designed to train the wandering eye to work together with the normal eye. The girl responded very well because the next day she walked into the Vision Training class like a little princess. She had been without glasses for most of the day and she could now make her eyes converge on close objects and she could see the phantom cross on the string, which indicated that both eyes were working and converging towards the object she wanted to see. After a few more sessions her eyes were functioning normally and would only begin to diverge slightly if she was getting tired.
Another case involved a professional woman who had developed strabismus with the right eye moving out (exotropia). This happened shortly after she had to suddenly move house. It seemed that the stress had caused her eye to diverge. She had seen a number of eye doctors and they had all told her that surgery was the only way to correct her problem.
The woman had attended one of my Vision Training classes the previous year so she had some idea of what might be possible using natural approaches. However, she did not know exactly what to do.
Again I taught her the butterfly exercise designed to help co-ordinate the two eyes. Amazingly, after doing the exercise just a few times her eyes started to converge normally. This was a case where the divergence of the eye had not yet been firmly established. The human brain learns amazingly fast.
In most cases strabismus responds wonderfully to Vision Training. Obviously it is best to do the exercises with someone else, because you cannot see your own eyes and do the exercise at the same time.
How to test for strabismus
There are two simple tests you can make to determine the degree and type of strabismus by using a small penlight held at eye level from a distance. Shine the light into the eyes so you can see the light spot on the cornea. In normal eyes the spot will be right in the center of the black pupil. The more the eye diverges the higher the degree of strabismus.
Note that 1 mm displacement (called positive kappa if the eye turns in and negative kappa if the eye turns out) is considered normal.
The cross-over test is used to reveal the full extent of strabismus. The test uses an occluder (something that will cover the eye) and transfers it from eye to eye. The longer the occluder is held before transferring, the more disruptive it is to the fusion. This test is also done with a semi-transparent material to reveal if there is latent (hidden) strabismus. If latent strabismus is present then the eye affected will turn behind the occluder.
Vision Training principles for strabismus
We assume that strabismus is caused by poor co-ordination of the eye muscles. The object is to teach the brain to balance the muscles so the eyes will converge properly.
• Train the eye co-ordination in order to correct the divergence.
• Encourage the brain to use both eyes and get three-dimensional vision.
• Deal with the near-sight often present in the divergent eye.
In Vision Training we think of the exterior eye muscles as if they were a hydraulic system. Ther
efore, in strabismus we need to adjust the setting of the muscle that is held too tense and to firm up the muscle that is relaxed too much. In other words try to encourage a natural balance in the way the eyes are co-ordinated.
How well does Vision Training work for strabismus? Clara Hackett, in her book Relax and See, writes of her strabismus cases:
There were 179 crossed eye students. 71 have achieved straight eyes and also have good fusion; 96 have straight eyes and good fusion except that there is a slight diversion from the norm when they are ill, emotionally upset or fatigued. 12 had no enduring improvement. (1955: 25)
This is a 90.5 percent success rate and is far better than what can be achieved with optical and medical methods. Children usually respond very quickly to Vision Training so the amount of time to be invested is usually only a few weeks and at the most a few months of daily training.
The wonderful thing about Vision Training is that the child is getting his or her normal vision restored. Clara Hackett’s results, as noted above, are typical. In continental Europe the focus of functional optometrists is the treatment of strabismus in children. It is a program that lasts for about a year with regular visits to the optometrist and promises a very high degree of success.
