Dear readers, I found this truth in the Internet about
myopia, and so I wrote the below essay to summarize and share with you, so that you
may take the precaution and save your children’s vision.
Myopia or shortsightedness is absolutely
preventable. In order to prevent myopia, let us first
understand its root cause.
Its root cause is the unusual usage of the
eyes in modern society, which require an unusual amount of close works like
reading, computer works, etc. These close works are usually carried out at a
comfortable distance of about 30 cm from our eyes, and for many hours. The eyes
therefore have to stay focused at this short distance for long
periods of time. Let us understand a bit more about focusing in order to
understand this root cause.
The scientific term for focusing is called accommodation. When we look at near objects, the eyes accommodate (try to focus) by contracting the ciliary muscle (internal muscle surrounding the lens), so that the biological lens is compressed (become thicker), and thus its power to bend the light rays, such that the focus point falls exactly on the retina (light sensitive layer) within the eye balls. The brain then receives a sharp image of the near object, but we hardly feel this effort of accommodation. It is an automatic action by each eyeball subconsciously.
On the other hand, when we look far, the
ciliary muscle relaxes, compression is lost, and the lens bounces back to
its original shape (flatter or thinner) again for parallel light rays
coming from distant objects to focus on the retina. At this stage, the
accommodation is zero, and the ciliary muscle is fully relaxed. This is the
best stage for the eyes. For details and diagrams, please see http://myopia.org/ebook. This is an important working
principle of the eyes when we look near and look far.
In terms of focus length, when the eyes accommodate, the focus length is shortened, but when the eyes relax, the focus length is lengthened. This forms the focusing range controlled by the ciliary muscle with a near end and a far end limit.
Now that you know when we are doing close work, the ciliary muscle needs to be constantly contracted (accommodated) in order to stay focused. Prolonged hours of accommodation without enough breaks in between will lead to spasm of the ciliary muscle, and this is phase I of the myopia process. This is a temporary phase and is reversible if the ciliary muscle is allowed to rest.
After a prolonged period of close work, say a few weeks to 1 or 2 months, depending on the intensity (how many hours of close work daily), it then enters phase II of themyopia process called elongation (or lengthening) of the eyeballs, where the eyeballs are stretched by the ciliary muscle with the support of high internal eyeball pressure during accommodation. Once an eyeball is elongated, it cannot be shortened again. That is to say, the phase II is an irreversible process! Thus prevention becomes very important.
In terms of focus length, when the eyes accommodate, the focus length is shortened, but when the eyes relax, the focus length is lengthened. This forms the focusing range controlled by the ciliary muscle with a near end and a far end limit.
Now that you know when we are doing close work, the ciliary muscle needs to be constantly contracted (accommodated) in order to stay focused. Prolonged hours of accommodation without enough breaks in between will lead to spasm of the ciliary muscle, and this is phase I of the myopia process. This is a temporary phase and is reversible if the ciliary muscle is allowed to rest.
After a prolonged period of close work, say a few weeks to 1 or 2 months, depending on the intensity (how many hours of close work daily), it then enters phase II of themyopia process called elongation (or lengthening) of the eyeballs, where the eyeballs are stretched by the ciliary muscle with the support of high internal eyeball pressure during accommodation. Once an eyeball is elongated, it cannot be shortened again. That is to say, the phase II is an irreversible process! Thus prevention becomes very important.
Myopia is essentially the elongation of the eyeballs, and it makes the retina layer further away from the lens. As a result, parallel rays from far objects focus in front of the retina, and thus far vision is blurred. Relatively, we can also say that the new retina's position is outside of the focusing range of the eyes. For every 1 mm increase in length, it is equivalent to 3 diopters or -3.00 in prescription, or commonly so called 300 degrees. So what is really changed is not our lens, nor the ciliary muscle, it is only the length of the eyeballs that changed permanently, and subsequently the power of the glasses we wear.
But for near vision, the myopes can see very clearly, and in fact, due to elongation, they can see diverging light rays from near objects effortlessly with little or no accommodation (adaptation to environment). This is similar to the weight lifters, their bodies grow muscle to adapt to the load.
The eyes are not designed for this unusual
prolong of close work, and it therefore adapts to such environment with this
elongation mechanism so that it can constantly see close up objects
effortlessly, and sacrifice the far vision. The majority of the
world's myopes are not born with shortsightedness, thus this type of myopia is
also known as acquired myopia and is absolutely preventable.
Before I start to touch on myopia prevention, let us look at a factor that worsens or speeds up myopia progression beside the above root cause (excessive amount of close work in today's society).
The glasses that are prescribed for myopes are usually minus glasses (negative power). They allow myopes to see far objects clearly by reducing the overall optical power, so that focus length increases to reach the new retina's position. Thus they solved the problem for far vision.
How about near vision? Do myopes need minus glasses to see near objects? Absolutely no! As mentioned, myopes can see near objects effortlessly without any glasses, and thus the term short-sightedness. But the advice given by optical shops is to put on the prescribed glasses at all time (except sleeping). So what happens when these minus glasses are worn for close work? The effect is very harmful!
Since diverging light of near objects focus nicely on the new retina position of the myopes without accommodating, wearing of minus glasses for near vision would make the focus point of a near object fall behind the retina, as it reduces the overall optical power and lengthens the focus length. Once again the myopes need to accommodate for near vision, they can no longer see near objects effortlessly whenever a new pair of glasses is prescribed. It is harmful in this sense that the minus glasses restore the need for accommodation and thus triggers the next wave of myopia process (phase I and II). Together with today's amount of close work (the root cause), the minus glasses help in accelerating the myopia progression (when used wrongly).
When the need for accommodation is restored, more spasm and elongation will follow in modern society, and the yearly circle goes on to have stronger prescriptions... This is especially true in children as their sclera (outer most layer of the eyeballs) is thinner and is more susceptible to stretching. Adults have stronger eyes with thicker sclera that is more resistance to elongation.
Before I start to touch on myopia prevention, let us look at a factor that worsens or speeds up myopia progression beside the above root cause (excessive amount of close work in today's society).
The glasses that are prescribed for myopes are usually minus glasses (negative power). They allow myopes to see far objects clearly by reducing the overall optical power, so that focus length increases to reach the new retina's position. Thus they solved the problem for far vision.
How about near vision? Do myopes need minus glasses to see near objects? Absolutely no! As mentioned, myopes can see near objects effortlessly without any glasses, and thus the term short-sightedness. But the advice given by optical shops is to put on the prescribed glasses at all time (except sleeping). So what happens when these minus glasses are worn for close work? The effect is very harmful!
Since diverging light of near objects focus nicely on the new retina position of the myopes without accommodating, wearing of minus glasses for near vision would make the focus point of a near object fall behind the retina, as it reduces the overall optical power and lengthens the focus length. Once again the myopes need to accommodate for near vision, they can no longer see near objects effortlessly whenever a new pair of glasses is prescribed. It is harmful in this sense that the minus glasses restore the need for accommodation and thus triggers the next wave of myopia process (phase I and II). Together with today's amount of close work (the root cause), the minus glasses help in accelerating the myopia progression (when used wrongly).
When the need for accommodation is restored, more spasm and elongation will follow in modern society, and the yearly circle goes on to have stronger prescriptions... This is especially true in children as their sclera (outer most layer of the eyeballs) is thinner and is more susceptible to stretching. Adults have stronger eyes with thicker sclera that is more resistance to elongation.
Thus, not wearing anything is much better than wearing the minus glasses wrongly, because low myopia would have no chance to be developed into medium or high myopiawithout minus glasses.
Therefore the mistake is not on the minus
glasses themselves but the wrong advice given! The correct advice should be
that minus glasses MUST be removed during close works - they are never meant
for near vision. You should only put them on when you need to see far objects,
for example, to see teachers' wording on the whiteboard, or driving a car, etc.
We are not being adviced or warned about this harmful effect of
these prescription glasses.
Let us now enter the prevention. We know that accommodation (focusing near) is no good for prolong periods of time, yet we live in a society with lots of close work. Children need to go through about 15 years of school life. Adults spend a long time facing computers. And thanks to Steve Jobs, now we have much smaller screens everywhere, people are looking at them at an even closer distance, and spent longer hours on screens too. It isn't his fault anyway, that is the trend. So how are we going to avoid accommodation in such a society? It would not be practical for us not to send our children to schools. How are we going to keep our eyes at a relaxed stage with these amounts of close work? This relaxation stage is what we want to achieve during close work, and it is the key to myopia prevention - the elimination of accommodation. This sounds like keeping the root cause (the unusual amount of close work) yet trying to get rid of the consequence (the accommodation).
Here is the solution, in contrast to the minus glasses, the plus glasses (convex) converges light rays, making diverging light rays from near objects become more parallel, the eyes therefore feel as if the light rays were coming from far objects (parallel rays), and accommodation is reduced or eliminated. Put it another way, with the optical power from the plus glasses, a normal person can now see near objects effortlessly without any accommodation, like a myope looking near without glasses. This stage of relaxation of the ciliary muscle allows close work to be performed for prolonged periods of time without leading to muscle spasm, and subsequently no elongation. That is it! Accommodation is removed and myopia progression is stopped. But please bear in mind that this only applys to close up work within 30 - 50 cm. If a normal person were to wear plus glasses for far vision, it would be equivalent to a myope, and the far objects would be blurred.
These plus glasses are exactly the same type of reading glasses worn by old age people as they become far-sighted, and they are very cheap too. I know you find it hard to believe that these old people's glasses are going to save your children' visions. You might even doubt if they will do more harm to children's vision. Let me tell you why people are in fear.
People fear the unknown, people fear when they don't know the truth, they don't know the working principle of the eyes. They fear because of their own ignorance. If you have the knowledge, you will not listen to the harmful advice. In fact you know what? The bi-focal glasses (top part is minus or zero, and bottom part is plus) is the safest glasses that can be put on at all time. When you look up, the top portion serves its rightful purpose for far vision. When you look down, the bottom portion removes accommodation while you do close work. If students were protected by such glasses throughout their school life, they can be graduated with normal vision. But once people see the dividing line on the lens they think such glasses are for the old folks and become resistant to it when applying to children. This is how ignorance we all are!
Let us now enter the prevention. We know that accommodation (focusing near) is no good for prolong periods of time, yet we live in a society with lots of close work. Children need to go through about 15 years of school life. Adults spend a long time facing computers. And thanks to Steve Jobs, now we have much smaller screens everywhere, people are looking at them at an even closer distance, and spent longer hours on screens too. It isn't his fault anyway, that is the trend. So how are we going to avoid accommodation in such a society? It would not be practical for us not to send our children to schools. How are we going to keep our eyes at a relaxed stage with these amounts of close work? This relaxation stage is what we want to achieve during close work, and it is the key to myopia prevention - the elimination of accommodation. This sounds like keeping the root cause (the unusual amount of close work) yet trying to get rid of the consequence (the accommodation).
Here is the solution, in contrast to the minus glasses, the plus glasses (convex) converges light rays, making diverging light rays from near objects become more parallel, the eyes therefore feel as if the light rays were coming from far objects (parallel rays), and accommodation is reduced or eliminated. Put it another way, with the optical power from the plus glasses, a normal person can now see near objects effortlessly without any accommodation, like a myope looking near without glasses. This stage of relaxation of the ciliary muscle allows close work to be performed for prolonged periods of time without leading to muscle spasm, and subsequently no elongation. That is it! Accommodation is removed and myopia progression is stopped. But please bear in mind that this only applys to close up work within 30 - 50 cm. If a normal person were to wear plus glasses for far vision, it would be equivalent to a myope, and the far objects would be blurred.
These plus glasses are exactly the same type of reading glasses worn by old age people as they become far-sighted, and they are very cheap too. I know you find it hard to believe that these old people's glasses are going to save your children' visions. You might even doubt if they will do more harm to children's vision. Let me tell you why people are in fear.
People fear the unknown, people fear when they don't know the truth, they don't know the working principle of the eyes. They fear because of their own ignorance. If you have the knowledge, you will not listen to the harmful advice. In fact you know what? The bi-focal glasses (top part is minus or zero, and bottom part is plus) is the safest glasses that can be put on at all time. When you look up, the top portion serves its rightful purpose for far vision. When you look down, the bottom portion removes accommodation while you do close work. If students were protected by such glasses throughout their school life, they can be graduated with normal vision. But once people see the dividing line on the lens they think such glasses are for the old folks and become resistant to it when applying to children. This is how ignorance we all are!
Lenses are lenses, no magic about them. Concave (center thin) ones we call minus glasses, convex (center thick) ones we call plus or reading glasses, parallel (same throughout) ones we call zero power or sunglasses or window glass.
Now that you know the key to myopia prevention - to relax the muscle
by eliminating accommodation during close work, we need to
handle a small issue here. There is a strong
relationship existing between accommodation and the convergence (turn
inwards) of our eyeballs on a near object. As we look nearer, accommodation
increases, at the same time, the 2 eyeballs also turn inwards in order to look
at the same near object. The plus glasses simply remove accommodation leaving
the convergence of eyeballs alone. This upsets the relationship and brings
about some discomfort to the external muscle that turn the eyeballs.
For children, this discomfort may not be too obvious as they have relatively shorter pupillary distance (distance between the 2 eyes' pupils). Thus the convergence of eyeballs is little compared to an adult, as adults' eyes are further apart. So what solution is there for the adults regarding this convergence issue?
The IMPA has a product called the Myopter, http://myopia.org/products.htm. It fools the eyes and removes the discomfort by duplicating the view image into 2 images, and places 1 on the left, the other on the right. Therefore the eyes don't have to converge as there is 1 image on each side, and the brain will superimpose them. Together with plus lenses, the Myopter removes both accommodation and convergence, therefore allowing prolonged close work without the discomfort. They are suitable for both adults and children.
As indicated in IMPA site, the correct way of using the Myopter, after the appropriate lenses are inserted, is to hold the books just beyond the far end of the clear zone, where the words are just started to get a little bit blurred, but still able to be read. Such a distance allows the ciliary muscle to have maximum relaxation.
But when people hear the word blur, they are in fear again. This is because they were told that the "eye strain" from trying to see a blur vision worsens the myopic eyes, and they must quickly go and get a pair of prescription glasses so as to see things clearly. To their ignorance, the exact opposite is true - the eyes are actually at their most relaxed stage when they can't see far objects clearly. If you still remember the first principle in the beginning, the eyes accommodate when we look nearer, and relax when we look further. Far vision is always good for the eyes regardless whether they are clear or blurred, you just have to know that your eyes are relaxed and don't worry about blurred vision. We all know that the details of a miles away mountain are always blurred no matter how good is your eyesight, so have no fear and stare at the mountain.
For children, this discomfort may not be too obvious as they have relatively shorter pupillary distance (distance between the 2 eyes' pupils). Thus the convergence of eyeballs is little compared to an adult, as adults' eyes are further apart. So what solution is there for the adults regarding this convergence issue?
The IMPA has a product called the Myopter, http://myopia.org/products.htm. It fools the eyes and removes the discomfort by duplicating the view image into 2 images, and places 1 on the left, the other on the right. Therefore the eyes don't have to converge as there is 1 image on each side, and the brain will superimpose them. Together with plus lenses, the Myopter removes both accommodation and convergence, therefore allowing prolonged close work without the discomfort. They are suitable for both adults and children.
As indicated in IMPA site, the correct way of using the Myopter, after the appropriate lenses are inserted, is to hold the books just beyond the far end of the clear zone, where the words are just started to get a little bit blurred, but still able to be read. Such a distance allows the ciliary muscle to have maximum relaxation.
But when people hear the word blur, they are in fear again. This is because they were told that the "eye strain" from trying to see a blur vision worsens the myopic eyes, and they must quickly go and get a pair of prescription glasses so as to see things clearly. To their ignorance, the exact opposite is true - the eyes are actually at their most relaxed stage when they can't see far objects clearly. If you still remember the first principle in the beginning, the eyes accommodate when we look nearer, and relax when we look further. Far vision is always good for the eyes regardless whether they are clear or blurred, you just have to know that your eyes are relaxed and don't worry about blurred vision. We all know that the details of a miles away mountain are always blurred no matter how good is your eyesight, so have no fear and stare at the mountain.
I would like to share a bit about the lasik surgery. While people might tell you that lasik is a good solution to myopia, I would like to tell you the following truth. Money is beside the points.
- Lasik doesn't shorten your eyeballs.
- Lasik is equivalent to wearing a permanent
pair of minus glasses that cannot be removed during close work.
- Like any minus glasses, there is still the
possibility for myopia progression, especially in children.
- Thus lasik is not a permanent solution as
it doesn't remove the need for accommodation. Prevention is
still better.
Lastly, myopia is the cause for retina detachment many years later which can lead to blindness. Educate yourselves and you can save your children's vision. Please visit http://myopia.org/ for detail.
Lastly, myopia is the cause for retina detachment many years later which can lead to blindness. Educate yourselves and you can save your children's vision. Please visit http://myopia.org/ for detail.
