In normal vision your eyes will converge on the object you are looking at. Your eyes will turn slightly inward so the image is located at the centre of the retina and fall on the fovea. The angle depends on the distance to the object in view. For example, you are now looking at this page, so your eyes will be converging on the page and your eyes will be turned inward slightly. When you look out the window or across the room your eyes will adjust their angle to converge on the object you are looking at.
With convergence you have depth perception and experience the world in 3D. The brain automatically fuse the image from your left eye and right eye together into a three dimensional image.
Lack of convergence or stereo vision usually does not affect reading but may affect ballgames and other sports where it is important to judge distance. People with monovision using only one eye generally develop alternate ways of judging distance.
It is believed that stereoscopic vision is developed by 4 months of age and will be fully established around 8 years of age. Generally it is assumed that the visual system is fully developed around the age of 8 years.
Severe convergence problems develop when one of the eyes turn 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 cross the midline of the retina the brain suspend the image from that eye in order to avoid double vision. You may not even be aware of this before you are tested.
Slight convergence errors are often part of peoples vision problems. The blur may not be due to near-sight but rather to the fact that the eyes actually converge a little before the object you are looking at causing the image to be slightly blurred. If the eyes converge in front of the object viewed you will experience a slight doubling of vision. The same will be the case if your eyes are converging slightly behind the object you are viewing.
To illustrate this phenomena try this experiment. Hold up a pen or a finger in front of you. When you look at the pen/finger the background will be blurred and appear double. When you look at something at a distance you will see a blurred image of two fingers in the foreground. Looking at the near object your eyes converge on the pen/finger and the background will be beyond your point of convergence so it will appear double. Normally our attention is on the object of interest and we hardly notice the background.
How effective is vision training?
Vision Training is very effective in correcting coordiantion problems. The exercisses give the brain a goal to work towards. The mind will automatically make the adjustments.
An 11 year old boy in one of my Magic eyes classes in Hong Kong said that he was a poor basket ball player because he could not get the ball into the basket. When testing the eye-coordination we discovered the reason why. His eye-coordination was a mess.
I asked him to get his dad help him cut five pieces of string, each one about four metres long. I told them to tie knots at every ten centimetres and mark them with bright colours, to make them easy to see. Then I told him to ask his dad to help him fasten one string in each of the two upper corners of the room and one string in each of the two lower corners of the room (as seen in front of him when he was sitting on the bed). The final string was to be tied to the doorknob.
I told the child to sit on the bed when everything was ready and to gather the other ends of the five strings onto his nose. The final task was for him to start putting an “X” on all the knots in the room.
The next time I saw him again he was beaming because in the last basket ball game he scored 3 times. Now his eyes knew where the basket is.
So it's easy to know how to throw the ball into the hoop.
Another example of how eye-coordination can affect reading. Lars's father said that he did not like to read he preferred sports. After fixing his eye-coordination problem Lars all of a sudden wanted to read his sister's Harry Potter book. Because now he could read for pleasure and without strain. It was that simple it took and hour and Lars was fine.
It is also important to check the ability to make rapid changes of focus from book to class room board and back. Demands in the classroom require a broad range of focusing distances ( its called “accommodative amplitude” ) from book to classroom board and back again. Both eyes must have power to focus as well as converge at both near and far quickly and accurately.
Some children have difficulty copying from the classroom board to their workbook because they do not know where they are. They have to read from the beginning every time they look up. Normally you can read half way down a page, look up and answer a question and your eyes will automatically point to the next word on the line where you left. To do this require a normal accommodative vergence function.
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"My son has been using Leo’s exercises for the past couple of years and has, by doing so, gone from a point where we were practically accused of child abuse by his school nurse for ignoring his deteriorating eyesight and not getting him glasses, to the point now where he is learning to drive glasses free, which thoroughly vindicates our belief in Leo’s methods.
This is powerful stuff which should be taught in schools – rather than carting kids off to the opticians to condemn them to a life behind glasses. I urge everyone who wants to solve their eyesight problems to try Leo’s methods. Attending his workshop is by far the best way of doing this but, If this isn’t possible, Leo has written 3 books covering his methods"
7月14日第一次到工作坊時，子敬有 300 度的近視，眼睛疲勞沒有神采，我們用 Leo 教授的繩索練習法和會聚力練習法回家積極練習，到7月15日的傍晚，子敬的近視已經降到 100 度以下了！簡直不可思議！7月16日第二次到工作坊時，看著 Leo 用視力表來訓練餘下的 100 度近視和用那有趣的小丑圖來治療省光，我已經由當初的半信半疑變到信心滿滿加上感激不已！
"My daughter Rebecca was diagnosed with strabismus, astigmatism, and long-sightedness at the age of 18 months. She was wearing glasses all day, every day from the age of 21 months. We had many stressful years of patching, drops, and exhaustingly long visits to the opthamologist, only to have her scripts get stronger over time. Rebecca could not be without her glasses, and as soon as she took them off, her left eye would turn harshly in.
As she grew older, Rebecca began to become more and more self conscious and felt that she stood out because of her glasses. She is passionate about her dancing, and has been performing since the age of 3. However, at the time of each concert she would express concern that she was the only one wearing glasses, and that you could not see her beautiful make-up properly! Yet she could not take them off as her eye would very clearly turn.
We discussed her concerns often, and she even tried contact lenses at the age of 8, however she resigned herself to the fact that she would always have her glasses. Her optometrist kept her hopes up by explaining that there was much research being done, and that operations were always improving. Her father and I were not comfortable with the thought of her eyes being operated on, and we explained that when she was older, the decision would be hers to make.
One night Rebecca saw an ad for a current affairs show which was airing a segment about getting rid of your glasses. She excitedly told me about it, and we made a point of watching it. Following the show, I made contact and booked Rebecca in for a children's workshop with Leo.
After many months of eager anticipation, Rebecca and I attended Leo's Magic Eyes workshop. Leo was able to quickly assess which exercises would be most important for each child in attendance, and we set to work!
The results of these simple exercises were almost immediate. Rebecca was so keen she was trying them in the car on the way home! After only the first session, for the first time in over seven years, Rebecca could take her glasses off and her eye would not turn!
This was a very emotional time for all of us, and we cannot thank Leo enough for his help. We have now been working on the exercises for a few weeks, and not only is Rebecca's turn rarely evident, her near points and far points have improved for each eye, and she has gone from wearing +4.5 lenses to +3 lenses. We still have a ways to go, but we are very determined!
Leo's knowledge is invaluable, and we only wish we had come across the techniques years ago. Our great dream for others is that Leo's strategies become the first point of call for children experiencing difficulties with their eyes.
All we can say is THANK YOU, THANK YOU, THANK YOU!
P.S. - Rebecca is keenly passing on information about the next workshops to others with glasses, even her teacher at school!