However, there are dark secrets which your opticians and optometrists are keeping from you.
This article aims to help you understand how glasses and contact lens correct astigmatism and the pros and dark side of using them.
Lois Lane: [after Clark uses his x-ray vision] So thats what you've been doing all these years when you pulled your glasses down. I thought you had astigmatism.
~ From the movie, Lois & Clark, The New Adventures of Superman
Before we get to the workings of corrective lens, let us dig in further on how light travel in an astigmatic eye so that you can better understand the mechanism nature of these prescription lenses.
The steepest and flattest part are 90 degree from each other. When this happens light is refracted different from the different meridians, thus causing a image distortion as it creates different focal points.
The creation of different focal points result in different type of astigmatism. They are:
Since astigmatism is most likely to accompany by other refractive errors such as nearsightedness, farsightedness and presbyopia, additional "cylinder" lens power to correct the difference between the powers of the two principal meridians of the eye.
Cylindrical lens has different angle of curvature in different planes (horizontal and vertical).
The cylinders refract the light rays at different angles from different meridians and focus them onto one spot on the retinal.
These glasses work well when the patient looks straight ahead but if you look to the side, things may still look distorted. Depending on the specific correction, the glasses can make the floor or walls appear to tilt.
To avoid this problem, some people choose to use toric contact lenses (more pricey option) to correct their astigmatism.
Toric lenses have greater light bending power in one direction than the other.
They contain a special cylindrical lens prescription that allow two prescriptions in one to compensate for the astigmatism.
As compared to normal soft contact lenses which conform to the shape of the cornea eventually, toric lenses stay in their shape due to its rigid gas permeable nature.
Toric lenses also provide a unique mechanism for keeping itself in the right place of your eyes, so the angles of your lenses are not affected and your vision remains crisp as you shift from object to object.
Am I trying to sell corrective lens here? Nope far from it. I just want to share with you all they work and their benefits.
Now let us see some of the darker sides of the story.
By now, I am sure that the intelligent you would realized that corrective lens treatment method is actually treating the symptom rather than the problem.
All corrective lens did was to refract the rays of light inwards and bringing the light into focus onto the retina instead of behind the retina.
Nothing about our eyes have changed. It is like taking pain killer to think that you are fine when in reality you are not.
Compensatory Lenses Does Not Correct The Problem
"The use of compensatory lenses (glasses and contacts) to treat or neutralize the symptoms does not correct the problem. The current education and training of eye care practitioners discourages preventive and remedial treatment."
Gottlieb, Journal of Optometry and Visual Development, 1982
Prescription lens can only fix your eyesight temporarily by refracting light differently into your eyes.
In fact, many times our corrective lens are over prescribed. Remember the sudden headache and giddiness when you first wear your glasses?
Those are the signs but your optometrist would tell you that you will get use to it.
"There are frequently ignored patterns of addiction to minus lenses. The typical prescription tends to overpower and fatigue the visual system and what is often a transitory condition becomes a lifelong situation which is likely to deteriorate with time."
S. Gallop, Journal of Behavioral Optometry, 1994
Little wonders on why we always feel tired when we put on the prescribed lens constantly.
As if that is not bad enough, there’s another problem with prescribed lens. They cause your eyesight to deteriorate.
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.
You may wonder what do all these have to do with astigmatism? When your accompanied refractive error (such as nearsightedness) get worse, so does your astigmatism.
I am not saying the corrective lenses are bad. It helped millions of people which includes me. I also wear them once a while. It is the over-reliance that we have to avoid.
Over-reliance on corrective lens will deteriorate your eye health which may lead to severe astigmatism eventually. Relying on glasses is like relying on crutches.
When our leg is broken, it is great to have the “crutch” to support us when leg is healing
But we don’t expect to use them for the rest of our life. When the cast is removed, the muscles of the injured leg have weakened and so we do exercises to regain its strength back.
We may depend on the crutches when in need.
As we practice, we wean ourselves off the crutches and, depending on the injury, can expect to regain most of our previous agility and strength.
Imagine if you depend on the crutches and not move your leg at all? Your muscles become weak and eventually wasted. If this is not your intention, something has to be done.
In order to reverse the damage, we must start removing those corrective lens now. Use them only on times where it is absolutely necessary.
Such as moments where you have to handle dangerous machinery, shooting, driving, checking out your dating partner... you get the idea. We need to stop relying on the “crutches”.
In addition, like all muscles, we have to do some rehabilitation work to regain our strength.
There is where eye exercises come to the rescue!
Eye exercises are a set of activities that aim to strengthen your eye muscles and increase their flexibility.
These in turn helps you to increase eyesight and slows down eye deterioration.
Pros: Instant effect, can be cheap, look smart(?)
Cons: Inconvenient, uncomfortable, can be expensive, astigmatism progression
Now we will move on to one of the less common ways to improve astigmatism. The Orthokeratology approach.