A sentence which I dont fully understand, please interpret

My dear fellow user,

Im trying to reduce my son´s myopia. One myopia user sent me a great link about child´s myopia and there is something I dont quite understand. Here is the paragraph:

"I generally recommend a much more nuanced approach to normalized prescription, for children. We want the child to see 20/20, on a well lit Snellen, being able to read about half of the line. If it’s all of it, if we get 20/15, the prescription is too strong. Just at the edge of 20/20, on a correctly done Snellen, allowing the child to see clearly.

If you give the child a 20/40 prescription, the frustration will be too significant, especially when you combine with enforcing close-up rules, having another pair of glasses for close-up vision, and limiting close-up time. We have to compromise."

It says we want the child to see all the way to 20/20 but only to half of the line? Does that mean, that the child should be able to read 20/20 but with quite an effort (it should not be straightforward)? Is that what this is trying to say?

Some optometrists consider 20/20 vision to be when you get at least half the letters of the 20/20 line right.
We don’t use active focus to measure visual acuity, so what he sees on the Snellen needs to be what he sees effortlessly. And in this case, the ““advice”” seems to be that without effort, he can get about half of the letters right (in good lighting).

A lot of adults seem to like their normalised to be more or less like this, actually. Adults might get away with reducing more but it doesn’t seem to be a very popular choice.

I hope this cleared things up.


Hi Salt,

thank you very much for the explanation. So I will basically wait until my son can read half of the 20/20 Snellen line quite effortlessly with his test lens kit and that will be his first normalised.

I must say that I used to reduce quite quickly for my own eyes as well, I was even down to -2.25 last year, and now Im going back up to -3D normalised! But I started with having -6.25D myopia, so it is still a great progress and I dont regret going back up with diopters.

Anyway, I digressed. There is another issue with my son. His glasses do have -1D myopia and -1D astigmatism carved in. Im not quite sure what to do about it. Shall I simply remove astigmatism completely, add 0.5D to his spheric and buy him -1.5D glasses? That was a suggestion from one user.

But Im not sure if -1D astigmatism isnt too much to be removing it completely cold turkey for the distance.

So this is the first thing I need to address before I buy him his first normalised.

I always wondered about this! So I guess I shouldn’t be blinking and AF-ing my way through my Snellen chart tests :smirk:

no as that would defeat the purpose. You wanna be able to see which lines could you see really well without an effort.

Therefore I was surprised that it is allowed for the kids to read 20/20 (without AF) but with a bit of an effort (like not needing to see all the letters on that 20/20 line).