Do you wonder how your optician or eye doctor work out the strength of your eyes?
Do you feel blinded by science when you are asked to look at various images of varying brightness on a screen? And when they input data into their PC and then comes out a confusing set of numbers?
Well hopefully after you have read this article, some of the mystery will be dispelled. You will be able to do this yourself either through making your own testing kit or by buying a gadget to do this for you. If you test your eye vision on a regular basis, you can see what progress you are making in your vision improvement and in that way, keep motivated to see even greater gains.
How to test your own eye sight with DIY tools
First up I need to say that none of these tests described below can substitute your regular eye check up exam. Your optician or eye doctor not only checks whether your current prescription is still good but also checks your eye health. This is vitally important and a DIY test is no substitute for this.
In terms of the test to check our current prescription though, is this always accurate? We put our faith in the optician or eye doctor trusting their training and the technology they use.
We are more likely than not to be over prescribed than under prescribed. Do you recall getting a new prescription and finding them too strong? The usual response from the optician is that strain will pass in a few weeks once your eyes have got used to the new lenses. But is that strain due to the lenses being too strong for our eyes in the first place?
On the Endmyopia.com web site there are various tools that you can make yourself to test your diopters (unit of measurement of the refractive power of a lens). There is also an astigmatism measuring kit.
The test for working out your diopters is simple. It just requires looking at the word ‘focus’ on the screen. When you are nearly out of focus looking at the word, take a measurement of how far back from the screen you are. You can use a tape measure for this. Then imput the measurement into the calculator (find it at http://endmyopia.org/focal-calculator/calc.html). If you have also imputed your current prescription as well, it will tell you if you have been over or under prescribed. The author does say this is best done in the morning before you start to wear glasses.
This simple test is done on the basis that a diopter is just a unit of measurement for how far you can see before you start to lose focus.
I used this test and did not find it terribly accurate (unless my eyes have dramatically improved recently!) My prescription 10 months ago was -4.75 in my right eye and -5.25 in my left eye. But this DIY test said both my eyes were -3.
Having said that, I did not do this reading in the morning as advised, so I might need to try this again.
The astigmatism measuring kit (find it at http://endmyopia.org/diy-tools-how-to-measure-your-astigmatism-diopters/) requires you to cut out a circular piece of paper and attach it to a dial with a paper fastener.
So not too difficult.
I was skeptical that such a thing could produce any where near to accurate results. But I was surprised by the outcome. The axis results were fairly similar although the cylinder results were less so. [take a look at my post on astigmatism for more details about these readings here]. Again, the author does advise taking a measurement twice daily for at least three days. Then take the average value from the readings over those three days.
How To Test Your Own Eye Sight with a Gadget
If you are not so inclined to DIY testing and taking readings over several days consider using a gadget to do this for you!
Eye Que sell a basic instrument (Personal Vision Tracker).
As you will see from the picture above the instrument is attached to your smartphone. You can store your results in the cloud. It tests the strength of your eyes and for astigmatism. These seems to provide more accurate and quicker results than the DIY testing tools.
There is a more substantial version (the Eye Que Insight 20/20 visual acuity screener). This is geared to checking the eyes of all your family members. With this you can check if your eyesight is still 20/20 with your current prescription glasses. Take a look at my review of the Eyeque Products here.
Why home testing is a benefit
Test your eye vision and you will be motivated to keep practicing your new eye habits. Its just like when trying to lose weight. When we don’t feel or look any different in the mirror, it is easy to get discouraged and think what’s the point!
All pain but no gain!
But once you step on the scales and see a lower number than you have seen previously, or for a long while at least, that is a great motivator to keep going. Even if the change is modest. At least it is a change in the right direction.
Likewise, if we have something readily available to check our eye sight then that will give us a great boost just to press on and achieve our goals. Just like weight loss, this takes time but the end result is surely worth it.
Reading your Prescription
Once you have taken your readings what are you going to do with it? I suggest that you compare it with your last eye examination results.
But what do you need to look for on those results?
Well, for those of us who are short sighted, we first get a sphere reading (or OD/OS standing for Oculus Dexter (right eye) and Oculus Sinister (left eye) respectively) which is a minus figure. This refers to the power of the lens in diopters. The larger the minus number, the stronger the lens.
Then the test will provide further results for any astigmatism (axis and cylinder results as stated above) you have.
Comparing the results may surprise you. You may have been over prescribed. A trip to another eye doctor or optician might be needed to correct this.
Being Able to Test Your Eye Vision is Essential
When you can take these readings any time any place, you take back control.
“These are my eyes and I will see progress!” You can say.
No more of just sitting passively back waiting for when the next test rolls around a year or two years later hoping the results will not have gotten worse.
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