Newbie w/ Contact Lens vs. Glasses Question

Hi friends! I’m new to EM but happily I am already seeing gains in the last week or two. It started with discovering EM on Youtube and the podcast, after which I started wearing my contact lenses only when I go to the gym, and wearing my (3 year old) glasses the rest of the time. Now I actually can’t wear my contact lenses any more because they feel so strong they give me headaches and make me feel dizzy. Crazy!

So I’ve already ordered a new pair of differential glasses for at-home, because even my 3 year old glasses are stronger than what I need for at-home activities like reading, phone use, or watching TV. I can almost get by with no glasses, but not quite. I definitely need some norms for the gym though, so I want to get contact lenses for that.

Now to get to my question. I’m going to give my diopters just so my question is clear, but I’m NOT asking for diopter specific advice just to be clear :slight_smile: I’m just confused about the concept I’m about to describe.

My current glasses prescription is
OD -1.75
OS -2.25
So there’s a difference of 0.5 diopters between my eyes.

My current contact lens prescription is
OD -1.5
OS. -2.5
So here there’s a difference of 1.0 diopters between my eyes.

Is this normal?? When I’m not wearing any glasses or contacts I don’t feel like there is a big difference in my vision from eye to eye, so I’m thinking about ordering my normalized contact lenses with only a 0.5 or 0.75 difference between the two, but I don’t know if reducing diopters and then also messing with the difference between the two is going to totally mess me up. Anyone have experience with this?

Also - Anyone have a recommendation about where to order contacts from?


Join the club! This is the point it all suddenly becomes real.

I can give an example from my experience: I was wearing OD/OS (right eye left eye) -5.50/-5.00 since 2015, with a difference of 0.50 between my eyes. An eye test taken in 2018, the last before finding out about EM in 2019, came as OD/OS -5.75/-4.25. From 2015 to 2019 I still wore the first pair of glasses, and I thought everything was fine. After starting EM, the eye test results and the difference of -1.50 was more accurate for the purposes of reducing diopters than the result from 2015 of -0.50. This means my left eye was over prescribed by -0.75 diopters.

What I’m saying is there’s a solid chance your contact lens prescription is overprescribed to some degree, yet you didn’t notice that because good vision doesn’t make you think anything is wrong. A 0.50 diopter difference is within the range of ocular dominance according to Jake, a lot of people will naturally have that anyway. If you’re saying you don’t feel a big difference between your eyes without glasses, I’d lean towards your plan of a 0.5 or 0.75 difference between the two eyes. You might want to look into centimeter measurements so you can see how the difference between your eyes changes over time.


Yes! It was so awesome to realize that the concept was already working for me before I had even really put any conscious effort into it.

Okay so if I’m understanding you right, it sounds like I should put less emphasis on my latest prescription and more on the centimeter measurements I come up with on my own?

Have you had any experience yet with totally equalizing your eyes?


Welcome to the forum :slight_smile:

No, this sound like a totally incorrect prescription even in the official opto world. With low myopia like yours, the contact lens prescription should be the same as the prescription for the glasses.
(with myopia above -4.5 D Sph the contacts prescribed are weaker than the glasses as with that level of myopia it starts to matter if the correction is sitting on your eyes or a few cms in front of your eyes)

The only exception is if you have cyl in your prescription, then the cyl may get converted to sph to avoid having to order toric contacts (which is a nightmare with the weighted bottom mark and the rotation on the eye).
E.g. if your glasses prescription was OD -1.75 SPH with plus 0.5D cyl and OS -2.25D with minus 0.5D cyl, then it would result in the contact prescription you have, but then optos don’t mix minus and plus cyl within a prescription.
So yes, it looks messy and abnormal in my opinion.

((the other exception would be if your opto was training you for monovision. Not recommended for EM))

For “no prescription contacts” check this link

With low myopia, it is best to determine the correction needed by looking at the Snellen (to get around 20/25 or 20/40) and at street and shop signs and licence plates (to be able to read them at about 4 cars’ distance). You want some blur but not too much blur. And you definitely don’t want to ruin your activities and or outdoor time by struggling to see or by missing to notice things.


Yes, centimeter measurements using Varakari’s Vision Log Tool will be helpful. If those measurements point toward 0.50 instead of 1.00, I’d go with that. You will also begin to get a feel for how much blur is good or bad for distance vision, which is another part of the puzzle. You basically take a bunch of inputs (distance vision, centimeters, snellen chart) and put it together to conclude a good idea for correction.

Yes. In my experience it’s identical in every way to improving both your eyes at the same time, just in one eye.


Now there’s a new insight I didn’t know, and explains why my contacts used to be lower than glasses. I feel like I can give contacts advice better now :grin:

Check point 1 and the embedded vertex distance link

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Ahh okay I guess I should have included my cylinders in the info! I didn’t include my Cyl because I wasn’t planning on messing with it yet… But it makes sense that this could affect the Spherical. Here is my actual prescription including the Cyl:

OD -1.75 SPH | -1.75 CYL
OS -2.25 SPH | -1.00 CYL

OD -1.5 SPH | -1.75 CYL
OS -2.5 SPH | -0.75 CYL

As I mentioned, I can ALMOST get by without glasses at home, but not quite. On my daily walks and when I’m at the gym I definitely need a little correction but now I’m wondering… Since my myopia is pretty low, is it that important to get my measurements “perfect” or can I still make improvements if it’s just “close enough”? I don’t know if I’m overanalyzing, but I think my main concern is trying to reduce too fast on my norms and not making any progress.

Thanks for the help!! :blush:

Ah ok.
1.00 D cyl = 0.50 D sph
It’s still a funny adjustment from your opto (selling you what toric contacts were left on the shelf and adjusting accordingly? or why would he/she reduce sph in one eye and cyl in the other? strange…)

With high cyl like yours you most probably have directional blur (higher blur on one axis), and that explains why you cannot get by without glasses even with low myopia. This is normal and will improve.

I started from around -2.00D, too, but only with a tiny & negligible cyl. Based on my experience on my journey I’d vote for relying more on vision experience than on overanalysed measurements. I measured a bit but then made a decision on what corrections to buy and had an idea what visual acuity I wanted to achieve with them. If the corrections chosen didn’t deliver the required acuity, I modified the corrections.

You should not be in a situation that your corrections are so weak that you can only function e.g. in a take away place if you take a photo of the menu above the counter and zoom in on your phone’s screen.
Similarly, you shouldn’t just walk around in a blur in the street. You should get a correction which may not give you crystal clear vision immediately when you are just screening the street aimlessly but you should be able to read signs if you looked at them with the intention of reading them.
In other words, if you need to move closer to objects than other people would to see them properly => then you are undercorrected. If you just need 5 seconds extra to bring the image or text into focus with awareness then you have the right correction for improvement.
And apart from that, the most important is to not wear the full correction in close up activities, with screens and objects closer to you than 55 or 65 cms.


Okay this all makes sense to me! I think I feel confident enough to make an educated guess on normalized contacts.

Blockquote Similarly, you shouldn’t just walk around in a blur in the street. You should get a correction which may not give you crystal clear vision immediately when you are just screening the street aimlessly but you should be able to read signs if you looked at them with the intention of reading them.

I spend about an hour or so outside walking every morning. Would you recommend wearing my differential glasses for this, or should I get used to using normalized contact lenses to work on my distance vision, like reading street signs etc.?

This is what I ordered for my differential glasses:
OD -0.75 SPH | -1.75 CYL
OS -1.25 SPH | -1.0 CYL
So basically I just reduced my latest glasses prescription by 1.0 sph on both sides and didn’t mess with the cyl at all.

This is what I’m thinking about ordering for normalized contact lenses:
OD -1.0 SPH | -1.75 CYL
OS -1.75 SPH | -0.75 CYL
So basically reducing my right eye sph by 0.5 D and reducing my left eye by 0.75 D, again leaving cyl alone. I just feel weird because this isn’t that far off from my diffs, so maybe I should have reduced my diffs more, or maybe I should reduce this less :sweat_smile: I know 0.75 D is a big reduction for a first pair of norms but my current prescription is definitely way too strong.

Personally I would start taking on that cylinder if I were you. Your Sph is low enough to get pretty serious about that Cyl pretty early on. Ideally you want to be at spherical only when you are in the last diopter.
Also possibly you need diffs with only a little sph and some cyl


Tend to agree with the above.
As this is the first pair of glasses chosen by you, it would make sense to try and drop 0.5D cyl, assuming that was overcorrected, almost guaranteed. And if so I’d go for equal sph drop not to mess things up too much at the same time.
You are right that this is tweaking the general rule of “start with sph”, but people with cyl as high as sph usually need to tailor the method a bit… and have to prepare for a bit of trial and error to figure out things at the start.


Do I have to add back any spherical correction when I reduce cylinder? I’ve seen a lot of people talk about substituting some cylinder for sphere but maybe after I adjust to to this first pair of diffs and norms I can just tackle cylinder by itself?

So it’s fine to drop sph and cyl at the same time? Or only in this case since my cyl is likely overcorrected?

Only if you are taking off more than .5 cylinder. so for example if someone wanting to remove a full diopter of cyl they might manage it by dropping the first half diopter and then exchanging the second half for .25 of spherical.This approach works for many, but not for all.

Have you tested your correction on the Snellen to gauge if you are over corrected and get an idea of by how much if you are? That would help you sort if you could drop some spherical too. At any rate I frequently tell people for their first pair of normz it is a educated guess, glasses are quite cost effective on line; make your two best guesses, one safe and one a bit less so, then if the more daring reduction doesn’t work you can fall back on the safe pair. After the first pair it is much easier to know what you need.

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For the first drop, it’s OK. You already know that you were overcorrected on the SPH, so it doesn’t sound like an exaggeration to say that most probably you were overcorrected on the cyl, too.
Once you get to the first pair which gives you just the right challenge, you should alternate cyl drops and sph drops so your brain can follow the changes easier.
And at that stage you can insert a diopter gap reduction every now and then, too.

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Okay thank you for clarifying this! Would you say it’s too aggressive to drop 0.5 cyl each time I make a cyl reduction? And when it comes to equalizing, should I reduce only one eye at a time, or simply make a larger adjustment in one side?

I have not tried using the Snellen yet. I wound up order both diffs (glasses) and norms (contacts) with only sph reductions… but I’m thinking my next correction will be either a 0.5 reduction in cyl alone, or possibly a 0.5 reduction in cyl along with a 0.25 reduction in sph. Does that sound like a good approach?

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I think it’s worth it to get a standard eye chart to hang up somewhere, they’re under $10 on Amazon if you want the official one like they have at the doctor’s office, or you can just print one out on a standard sheet of paper.

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difficult to be sure, I would say almost everyone can get away with it once, after which some still manage to continue with .5 cyl reduction each time and others find they can only do .25 each time unless they add sphere back in.

If it happens that you are over corrected still (and really only your snellen can tell you this) it could work, but if you aren’t still over corrected then this would be a double reduction and I would not recommend it.

Just do the one eye when equalizing, it is called a monocular drop. when the time comes this article: Patching - EndMyopia Wiki and this video: Tag-In Method - YouTube should help.



My first pair of diffs just arrived in the mail yesterday and I immediately came to a bittersweet realization - They are still way too strong! :sweat_smile: I can unfortunately see way too clearly lol. I’m guessing that by dropping Sph only, and leaving Cyl alone, I didn’t make enough of a reduction to have any sort of challenge with close-up work.

I think it’s pretty clear that I need to make a reduction in Cyl now.