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Registered: 05-2005
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Prevelence and severity of myopia research


From the research ive done around the web, here is what ive come up with so far.


emmatropia
lacking any significent refractive errors. May have miniscule amounts of myopia or hyperopia -.5 to +.5 diopters. This is normal and does not need any action taken. Most people fall into this range and generally have perfect 20/20 vision to near perfect 20/30 vision.

mild/low myopia
-.75 to -2.75 diopters. At least 25% of americans are myopic. Among myopes, the greatest percentage falls in the mild category. 60% have a slight refractive error with resulting uncorrected vision of near perfect 20/30 to an inadequate 20/200. All low myopes should not be worse than 20/200 without correction unless they have signficent astigmastim, high order abberations or other pathelogy. Many of them are 20/100 or better and do not depend very much or at all on glasses. They also have it good in reduced dependancy on reading glasses when presbyopia comes.


moderate myopia
-3 to -5.75 diopters. At least 25% of americans are myopic. Among myopes, 30% are moderately myopic

severe/high myopia
-6 to -9.75 diopters. At least 25% of americans are myopic. Among myopes, 8% are severely myopic

very severe/high myopia
-10 to -15 diopters. At least 25% of americans are myopic. Among myopes, almost 2% are very severely myopic

extremely severe/high myopia
more than -15 diopters. At least 25% of americans are myopic. Among myopes, extremely severe myopia is rare, probably about .1%


breakdown:

60% are less than -3
40% are -3 or more
10% are -6 or more
2% are -10 or more
very few are more than -15

breakdown2:

60% are less than -3
90% are less than -6
98% are less than -10
nearly 100% are less than -15

breakdown3:

60% are -.75 to -2.75
30% are -3 to -5.75
8% are -6 to -9.75
2% are -10 to -15
very few are more than -15


Of course most of them will be in the lower range of a given bracket. Take the 8% for example, youll see alot more that are -6 or -7 than -9. Much of the 2% is -10 or barely above that. Few are near -15 and very few are over -15. While I have more to research on the percentages, my causal observations are in agreement. I see and know about twice as many people with thin glasses that they dont even always wear. I dont see very many severe myopes and I cant even remember/recall anyone more than -9

9/8/2005, 1:06 pm Link to this post Send Email to Myope5   Send PM to Myope5
 
terminator31 Profile
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Re: Prevelence and severity of myopia research


That sounds about right. A lot of people are myopic and don't even know. They're probably around -.5 or so. I notice a lot of people in my classes squinting, especially the ones in my programming class emoticon
9/10/2005, 12:52 pm Link to this post Send PM to terminator31
 
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Re: Prevelence and severity of myopia research


-.5 diopters isnt severe enough to need to squint and its still within normal emmetropia range. I bet they are probably -1 to -1.5 and 20/40 to 20/70
9/10/2005, 12:56 pm Link to this post Send Email to Myope5   Send PM to Myope5
 
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Re: Prevelence and severity of myopia research


more figures:

1 in 5 are -5
1 in 10 are -6
1 in 20 are -8
1 in 50 are -10
1 in 100 are -11
1 in 200 are -12
1 in 500 are -15
1 in 1000 are -17
1 in 2000 are -20
1 in 5000 are -25
1 in 10000 are -30


at least is what I think the figures are. Ill edit the post if any are inaccurate.
I see alot of low myopes, many that I would barely even consider myopic with their -1 diopter. I see about twice as many low myopes as moderate myopes. Many of the moderate myopes I see are in the -3 to -4 diopter range. I am probably in the high -4s or will soon be once I improve my vision more.
11/8/2005, 11:25 pm Link to this post Send Email to Myope5   Send PM to Myope5
 
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Re: Prevelence and severity of myopia research


Number of Occurrences
------------------------- ---------------------
           -18.75 1
           -13.00 1
           -12.00 1
           -11.50 1
           -11.00 3
           -10.25 2
           -10.00 2
           -9.50 1
           -9.00 5
           -8.50 9
           -8.25 3
           -8.00 6
           -7.75 1
           -7.50 6
           -7.25 6
           -7.00 23
           -6.75 3
           -6.50 18
           -6.25 1
           -6.00 17
           -5.75 17
           -5.50 28
           -5.25 15
           -5.00 33
           -4.75 32
           -4.50 30
           -4.25 33
           -4.00 70
           -3.75 40
           -3.50 43
           -3.25 44
           -3.00 59
           -2.75 60
           -2.50 68
           -2.25 55
           -2.00 68
           -1.75 84
           -1.50 62
           -1.25 43
           -1.00 84
           -0.75 74
           -0.50 71
           -0.25 63

This is the prevelence of myopia recorded by one optometrist. Keep in mind it just takes a small sample and theres some bias too because many low myopes see well enough to go infrequently or not at all. Also some of those pescriptions are subject to change.

11 people are -10 or more
99 people are -6 but less than -10
444 people are -3 but less than -6
732 people are less than -3

total is 1286 people

1 in 117 are -10 or more(below 1%)
1 in 13 are -6 but less than -10(7.7%)
1 in 2.9 are -3 but less than -6(34.5%)
57% are less than -3


57% are less than -3
43% are -3 or more
8.5% are -6 or more
few are -10 or more

Keep in mind again many of those low myopes simply didnt bother to get their eyes tested or the percentage would be considerabily higher. I was actually off when I said 2% are -10 or more, it turns out its less than 1%!!!! I was right when I said about 8% are -6 to -9.75! I am pretty close when I said 40% are -3 or more. I also came close when I said 60% are less than -3. I do think the percentages are somewhat skewed due to omission of low myopes not bothering to come in for an eye exam. However I dont count -.25 nor -.5 so the 60% figure of less than -3 is probably pretty accurate after all. If you refer to the first post, I stand by those figures.

60% will be low myopes less than -3
30% will be moderate myopes -3 to -5.75
8% will be high myopes -6 or more.


Lets refer again to this:

breakdown3:

60% are -.75 to -2.75
30% are -3 to -5.75
8% are -6 to -9.75
2% are -10 to -15
very few are more than -15


I would probably change the figures to:


62% are -.75 to -2.75
30% are -3 to -5.75
7%% are -6 to -9.75
1% are -10 to -15
very few are more than -15

Theres still much debate to the exact percentages and one would need to take a sample of everyone without omitting anyone. I know alot of very low myopes that dont regulary get eye exams and many dont even know they have any myopia. Guys like those would probably be your typical -.5 diopter which is way too low to take any neccessary action.

Pathalogic myopia is less than 2% and many with pathalogical myopia have double digit pescriptions. Notice theres a huge gap between the -13 and that poor guy at -18.75!






1/10/2006, 4:13 am Link to this post Send Email to Myope5   Send PM to Myope5
 
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Re: Prevelence and severity of myopia research


The reason we originally suspected the error was the incidence of myopia
that high is so rare as not to be believed. I've seen about 10,000
people (20,000 eyes) in my many years of practice, and the highest myope
I ever encountered was -19.00, about 20 years ago. From time to time I
see -12.00 to -15.00, but never have I personally seen a -23.00. I
wonder how many o.d.s on this group have seen -23.00 in their years of
practice? If you answer this, please post approx. the # of eyes you've
seen along with the highest myopias you've seen.

w.stacy, o.d.

p.s. the other reason we suspected an error is that a 23 D. myope's eye
is about 8 mm too long for its optical system. To achieve emmetropia
the eye will have to shrink almost a centemeter, or the cornea will have
to be flattenet 8 diopters (can you imagine that?), or a clear lens
exchange would be required.


I was right when I estimated 1 in 5000 people are -25 diopters. He may have never seen one but ive seen a few online. There was one -27 who posted on a lasik site asking if anything can be done. Even IOLs wont fully correct him! Diopters in the -12 to -15 range is rare but common enough that optometrists see one once in a while. Probably about 1 in 300 fall in that range
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