Ciliary Myopia Astigmatism
As you may have read in the guide, most astigmatism correction is entirely unnecessary in early myopia. That is to say, your first and second prescription of glasses, when you first experience myopia symptoms, should include no astigmatism prescription.
Why is this?
Astigmatism, especially when measured passively (using the autorefractor), varies from one measurement to the next. Every time your eye’s focusing muscle adjust for different distances, there is a small degree of imperfection, that the machine sees as astigmatism.
Since your focusing muscle is circular, and it has to make tiny adjustments to the lens on your eye, along with the changing distribution of tear fluid on top of your eye, the image you see is ever so slightly distorted.
But this is not something you will even notice. But the autorefractor does.
So you get a prescription, which now alters how light enters your eyes, all day, every day.
This is not a good idea.
Your eye now will adjust to the environmental change, and you will actually experience consistent astigmatism symptoms. Not correcting for it in your next prescription, may leave you with a blurred image, of symptoms of discomfort.
If you have a very low prescription (below -2 diopters), it may make sense to begin review and reduce astigmatism correction as part of your eyesight improvement goals.
Axial Myopia Astigmatism
If you have been myopic for years, and have a high prescription (over -4 diopters, commonly), your eyeball may actually have changed shape, to deal with your close-up strain (more detailed explanation of this, here).
In this case, astigmatism is a real symptom, not just what in all practical consideration amounts to a measurement error.
Once your eyeball elongates (deforms), you do need some astigmatism correction.
In this case, we first need to reduce your myopia, before we ant to start working to reduce astigmatism correction you actually still continue to require.
90% in 9 Months: Reduce Astigmatism
This is an average number, for the average myope. If you have low (ciliary) myopia, we can start reducing your astigmatism prescription right away.
If you have average myopia (-3 diopters to -4 diopters), within 90 days, you are likely at a point where you have reduced your myopia enough to where we can simplify your prescription complexity (more on the topic of harmful prescription complexity is here).
The goal is to have a straight (spherical correction only) prescription. This will mean the least confusing change, when you take off your glasses (in contrast, the more complex your prescription, the more difficult it is to adjust to times you are not wearing glasses).
If we start to reduce astigmatism at 90 days, by the time you reach 9 months, you are likely at zero astigmatism correction.
For lower myopes this can be much sooner, where clients often report not needing astigmatism correction in as little as 90 days.
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Of course you might also try a month of the Vision Improvement Program, to start taking action to reduce astigmatism, as well as eliminating your myopia and the need for glasses.
See you again tomorrow, for more on the topic of astigmatism correction, myopia rehabilitation, and related subjects to improve your eyesight.