Most people do not question the widely held assumption that donning glasses is the best thing that can be done for their eyesight problems. Very few people take time to consider what really happens when they put their glasses on, and why this is not the best solution.
The optics of glasses
Vision is not static. Your eyesight is in a constant state of change. This is a fact that most people are familiar with. For instance all of us have felt our eyes becoming tired after a long day in front of the computer.
Glasses are fitted in order to correct refractive error. In other words, the lens is supposed to focus the image that we see precisely onto the retina. However, glasses compensate for the refractive error in an unflexible way. When worn, the particular level of refractive error must be constantly maintained in order for you to be able to see through them.
This is further aggravated, as is often the case, if your prescription is for 100% correction at the exact time of measurement. This is because your eyes will have to constantly adapt to the conditions at the moment when your eyes were tested. So if you happen to have your eyes tested in the evening after work, your eyes will always be forced to adapt to those conditions, even if they are false. You may have experienced this when putting on new glasses for the first time, only to find that the prescription hurts your eyes. When you complain about this the answer is usually, “You will get used to them in a few days.”
What will happen to your eyesight with this continuing situation? Obviously your eyes have to adapt themselves by constantly maintaining the refractive error the way it was that evening when your eyes were measured. In other words your eyesight is forced to deteriorate, just so the glasses will fit.
Why using minus lenses for reading is bad for the eyes
Using minus lenses for reading actually makes your vision worse.Here are the scientific reasons why this is true. Near-sighted eyes have to over-accommodate or adjust three dioptres in order to read at a normal reading distance. So, if you wear –3 diopter lenses for correcting your vision at a distance and keep your glasses on for reading, then your eyes have to adjust for the 3 diopters normal people need, as well as to the –3 diopters in the glasses. In other words your eyes are required to adjust/ accommodate 6 diopters for as long as you wear them for reading.
This is the reason why using glasses designed for correcting your distance vision whilst reading is bad for your eyes. This additional strain on your eyes can only have a detrimental effect on your vision. Instead, either take the glasses off, or read whilst looking over the frame.
Your near sight glasses are proscribed to provide clear vision from 6 metres to infinity. Since the glasses are static, they will be 20 times out of alignment if you use them for reading at 30 cm. If you look at something 3 metres away they will be 50% or half wrong. This fact is difficult to get around if you wear glasses. At this point in time it is not possible to construct glasses that vary their power as you change from reading to looking out of the window. Your video camera has the capability to do this by moving the lens elements back and forth to keep your video in focus.
Importance of the optic centre
The lenses in all pairs of glasses have only one point of best vision - the optic centre. This means that they are constructed as if you were always looking through the dead centre of the lenses, with this centre located directly in front of your eyes as you look straight out in front of you. When you look through the glasses and turn your eyes away from this centre, the lenses become more like prisms. You have probably seen this effect on photographs taken through wide angle lenses. The edges of the image get distorted. This, along with the fact that glasses also have some sort of frame, encourages you to keep your eyes locked into the position that gives best vision. A frequently used practice in the attempt to control diverging eyes is the fitting of strong plus lenses. This is a treatment that sadly ends up driving the vision further downhill.
The optic centre also plays a role when you use lenses for reading. Remember, your glasses are prescribed with the intention of correcting your distance vision. When you look at the horizon your eyes point straight out through the optic centre of the glasses. However, when you read you turn your eyes in and down in order for your eyes to converge on your book. Unless you wear special reading glasses, or have them incorporated into your glasses, the optic centre of each lens will be further apart than required. The result is additional strain on your eyes, the more you read the greater the damage.
If you wear near sight glasses whilst working at a computer, they will be wrongly adjusted for both reading at about 35 cm and the computer screen at 60 cm. This is a contributing factor to the way that computer work affects the eyesight.
Does wearing glasses affect the size of your eyes?
Shockingly, there is ample scientific evidence that lenses fitted on young primates affects the development of their eyes.
In research at a New York University, biologists have demonstrated that wearing a minus lens actually causes the elongation of the eyeball, in other words it causes near sight to deteriorate. The same is the case with plus lenses fitted for presbyopia or far sight. This research into emmetropization, the eyes' natural ability to develop clear vision, goes back to the early 1990s.
Of course the idea that glasses make your vision worse is resisted by the optic industry. Just as tobacco smoking is not considered harmful by the tobacco companies.
The annoyances of glasses
Wearing glasses is at best a compromise. Everyone knows that the solution to clear vision is not found in glasses. They cause many annoying inconveniences. Just remembering where you've put them can drive you to a point of frenzy! And how annoying it is when they fog up when the humidity changes as you go from inside to outside. They also get dirty, scratch, break etc. at the most inopportune moments.
With the Vision Training approach, our objective is to completely eliminate the need for glasses by means of exercises. Our goal is natural clear vision - nothing less.
Kennebeack, J.J., Why eyeglasses are harmful for children and young people, 1969, Vantage Press.
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