Difference between "a little bit of blur" and "visual cortex will tune out now"

I can’t figure this one out, so need a bit of help. Maybe its not that important but I feel stuck on this.

I keep reading about the need for having a “little bit of blur” for stimulating AF and subsequent reductions. But I can’t figure out what that “little bit” actually means. Like literally - where is the line between too much and too little? Where is too much blur becoming strain and “your visual cortex turning off” kinda thing?

In my normalized pair, I can see 20/40 on a good day, with good lighting and still somewhat blurry. Not perfect at all, but I can make out the letters. When I go with these glasses outside, they feel fairly sharp to me, I can see a lot, even if not perfect, but they feel great. They also feel pretty good enough for driving. There is still a bunch of stuff that’s far away that I can’t see well. So I do have more than enough blur, but I also have a lot of stuff that I see clear.

How clear do I need to see to be able to say - yeah, its a little bit of blur, and not too much? Is there like a rule of thumb for this?

I’ve spent the last 15 years being very undercorrected on purpose, so I don’t have a concept of how sharp/blurry am I supposed to be seeing.


I’d start with whatever full correction gives you maximum visual acuity, so you look at something and that’s as sharp as it ever gets for you, and then back off to whatever gives you 20/25 or so, with the goal that you’d like to active focus back to “as sharp as it gets”. I think it’s less desirable (maybe still useful) to go from “pretty blurry” to “less blurry”. Ideally you want active focus to take you from “almost there” to “all the way there”. You want to go from “a little fuzzy” without active focus to “sharp”.


Maybe for the word “FOCUS” the second or third row from the top before you blink to the 4th row or the bottom row (ideally the bottom row) when you’re looking at a street sign or something like that.

You don’t want to be used to or satisfied with the top three rows of the “FOCUS” image even though those are still readable.

From the way you describe it I’d add in more minus correction on your normalized so that you’re seeing 20/20 on good day in nice light and 20/40 or better in less-than-ideal lighting, with an aim to active focus it to 20/20 or better. You want to be picky about small amounts of blur rather than accepting of less-than-sharp images.

You don’t want to be over-corrected so that there’s no blur at all ever even in bad lighting when you’re not making any effort to focus at all.

Put another way, you want to keep bringing it back to total clarity through active focus, rather than having no opportunity to active focus (over-corrected), or no opportunity to get to total clarity (undercorrected by too much.) It’s not the easiest thing to describe.

I think @BiancaK or @nottnott has a car license plate example infographic that has some text that says “don’t put up with more blur than this”-- I can’t find it.

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You see some blur. When you look at something for several seconds, does it get clearer?

I love that license plate image. Unfortunately the first 2 look the same to me. I have to measure 3 meters and look at some cars to check distance.


The little blur means that if you casually look at something then you have some blur but if you bring attention to it then the blur clears up. And then you train your eyes to hold that “attention / awareness” longer and longer until it happens without conscious attention. If you cannot clear the image fully by following the edges of the letters with your eyes then you have too much blur to clear.

20/40 is at least 0.75D missing from the visual acuity.

EM is not about spending the day looking through blur. (Those are the other “throw your glasses away methods” that can bring a max 1D improvement by releasing the ciliary muscle spasm and there are rare exceptions who achieve more with this method)
The improvement part of EM is about spending the day in almost full clarity with the help of bringing attention to looking / watching.


What you can do is to look at the same live object at distance with your normalised and then with a pair of glasses -0.5D stronger. You will notice differences in acuity and then you can decide if seeing those details are normal or supernormal (= over corrected eagle eye details)
For me the difference was that with 20/20 I could take in the full image at once, i.e. read the licence plate and within the same quick look I also took in the info about the brand the type and the colour of the car, etc. With the reduced distance vision correction I could read the licence plate OK but I was so focused on it that I missed the other details. Clear sign that it needed a lot more (semi-unconscious) focusing to see the licence plate “clearly”.


I don’t think your question about “how much blur” is naïve at all. And all these graphics presented to you about blur say nothing about the distance. Everybody gets blur with suficient distance. The significant difference is not only in the amount of blur, but in the amount of distance.



The interesting question (for me), is what should it look like after applying active focus.

That’s an interesting question for me because AF is so ingrained in seeing now for me after two years of EM that it’s a bit of a challenge to totally turn it off.

Thus my “edge of blur” is a barely slightly blurry view when a good amount of active focus in use. I choose glasses to achieve this for whatever distance I’m looking at (e.g. distance, PC or phone). It’s like holding a carrot just barely out of reach, I can almost clear the view, am close enough to clarity that my eyes/brain really want to get that last iota of clarity but just can’t yet.

This way I know that I’m using good AF (because the view gets noticeably blurrier if not)

I don’t know if near-maximum-effort active focus for hours a day makes me improve faster than a less intense habit, but it does let me check if my eyes are being honest, and not just relaxing because my prescription is too strong that day and I didn’t realize it :slight_smile:


Thank you @NottNott for the image! It’s great and makes it clear that I need to be very very close to the blur edge. It clarifies a lot for me. So thank you! I didn’t realize I need to be that close for it to work.

A follow-up from this - I get here is that there are 2 factors in the equation - the strength of the glasses and the distance from the edge of the blur. So if I can’t see the license plate as in (2) from a distance or 3 meters, I could just get a bit closer to the car, so that I am not in (3) or in (4). It would still be distance vision, as 20/40 is not up close doing AF on my computer. Why is that not good enough?

If I can kinda see 20/40 with my normalized, it means that my vision bubble is slightly smaller, and so what? Can’t I still do plenty of AF in that bubble? Why do I have to do it for a car that is 3 meters away from me? I could do it for a car that is 2 meters away as well if that’s where my bubble ends. Right?

Yes, I could wear my full 20/20 glasses all day long, but I am not bird-watching all day. I just sort of live in a “regular-sized” bubble - I spend a lot of time at home, with kids, cooking, working, shopping, and other normal day-to-day activities. I can find plenty of AF opportunities doing this. I can do AF when grocery shopping, or walking in my neighborhood, when looking at signs - and yes, I might see these at 20/40 distance, but why is that not good enough? Why do I need to be at 20/25 or so all the time, except if I am on the computer or reading? It feels uncomfortable and too strong for many things I am doing.

I am not trying to argue with the method. Not at all. I believe it works. Just am truly struggling to understand this point, which I think is crucial here.

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I use undercorrected norms all the time, unless I’m driving or know I’ll be outside for a while. I’m so paranoid about using my ciliaries that I’ll live with blur beyond what I should, because I know I get plenty of AF when outdoors or on my PC or phone. My goal otherwise is minimizing ciliary use, while having enough correction to live my day.

Granted that’s extreme, and you don’t need to be that fanatical, I’m just a bit OCD in this area :wink: The two axioms of EM (my version at least) are to maximize AF opportunity while minimizing ciliary use, especially extended-time ciliary use.

The theory is simple: ciliary use pushes the eyes myopically, while active focus pushes the eyes hyperoptically. Since my current goal is hyperopia stimulus, I maximize one (active focus), while minimizing the other (ciliary use). All of EM falls out naturally from those two axioms.

So do the math, figure out what prescription(s) you need to maximize active focus opportunity, and choose glasses for the situation to do that, or at least, to minimize ciliary muscle use.

That’s all norms and diffs are. Normals are for AF opportunity while outdoors looking at distant stuff. Diffs are for minimizing ciliary muscle use and intensity when you have to look at near stuff (like PCs or phones/books). I just happen to choose from several diffs to give me blur challenge (AF opportunity) at several distances, including PC use. I’m also at the stage where I can use phones uncorrected comfortably, allowing yet another AF opportunity via “print pushing”, which turns a problem (phone closeup use) to an asset (AF opportunity).

To me nothing else matters. Get AF opportunity however you can, and use it to AF lots. Then focus on reducing/minimizing ciliary use, which is anytime
you look at something closer than the furthest you can see (without AF) with whatever correction you are currently wearing. That’s it, that’s EM (my version at least). Most of the other “rules” fall out of that and are honestly just attempts to Keep It Simple™ for newbies trying to learn the ropes, so to speak.


First of all I don’t know anything for sure, so with that big caveat in mind, there a a bunch of things going on with vision. In addition to “fine tuning” of focus there’s blur adaption which is where your eyes never quite get there with the fine tuning of focus, so your brain just does the best it can with the blurry signals coming out from your eyes. Maybe if you had an actual injury to the focusing mechanism of your eyes in the caveman days that would be a good thing. In your case you’re getting your maximum distance vision at closer in ranges where your eyes are still converging for near or middle distance (as opposed to bird watching distance :bird:). There might be some advantages to you of undercorrecting to a bigger distance bubble than a smaller one. Maybe not though. Since we’re self experimenting we’re all trying to find what works.

I’d try to get more AF practice in the great outdoors at bigger distances with a smaller undercorrection, but I can’t say with any certainty that you couldn’t do just as well using your method for a while.

Lighting levels outdoors are generally much higher outdoors than indoors, that might also help speed emmetropization along.

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You can AF at any distance. Just find the right combo of correction vs. distance.

As for glasses for driving:
In most countries the requirement is minimum 20/40 which equals to being able to read the license plate of a car at about 20 meters away. The glasses you wear for driving should give you that clarity. And that would still not be 20/20, just 20/40ish.
To be honest, I’m not convinced you have 20/40 with your current normalised.

More on distance vision here:


Haha, you might be right, and I have no idea either. If I can make out the 20/40 line on a good day with good lighting - does it mean that I can actually see to 20/40? Is it like a hard of soft science?
Everything is always a bit blurry to me up to the top of the chart, even if I can read the letters clearly.

We’ve discussed it in your other topic :wink: