Some help please


Just need some help please.

My routine is as follows, I wake up, no glasses for 20 minutes, and then put on my usual distance glasses on.

Once I start work I put my differentials on and will keep these on for a few hours whilst working on screen. In this time I will take breaks and practice active focus on the screen. I work with screens for most of the day.

I feel like I am wearing my differentials for most of the day and only using my typical distance glasses if I am not looking at any screens. Sometimes I find myself quickly interchanging between the two.

I go outside for my walk and wear my differentials. When I watch TV I use my distance vision glasses, but can use my differentials with a little blur, not sure which is correct?

I also feel that I can get away with wearing my differentials for driving, but again not sure?

Biggest uncertainty I have is should I be wearing my differentials as much as I am and when should I be using my full prescription glasses?

Any help or advice much appreciated.


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Differentials are just for screens - normalised are what you want for distance. Corrections that are too low don’t improve your vision, so differentials for distance vision in this case probably are not doing you any favours.

You should wear your normalised for everything that is not an up-close screen though. There is no benefit to really scrutinising whether you can ‘get away’ with lower correction for certain activities, or like having a pair of glasses for different activities etc.

I think you know where I’m going with this… so instead:

As @Lloydmom says, normalised are for your normal life. Look into getting a pair if you haven’t got some already.

I drove undercorrected ~2 years ago as well. That was in the reducing way too quickly phase of my EM journey. Put me off that idea for life. Don’t drive undercorrected, just thinking about it, is pretty scary. It’s like the only time you want to wear full, full strength glasses instead of normalised.


It sounds to me like your differentials might be too strong. You really want something that lets you see clearly to the screen and what’s on your desk and not too much further. They certainly should not be OK for driving. Usually you want something with 1.5 or 2 diopters less correction than your glasses for distance.

For the sake of argument someone with “full correction” of -4 diopters might wear -3.75 for “normalized” and might wear -2 for “differentials”. For driving he’d wear full correction. For watching TV or walking around outside he’d wear his normalized. For reading a book or working on a screen he’d wear his differentials.

Hope that helps you.


You mean for close-up differentials right? Norms for distance are usually a 0.25 reduction from full-strength.

Yes, that paragraph is talking about differentials.

Hypothetical example:
Full Correction: -4 (for driving or other dangerous activity)
Normalized: -3.75 (for outdoors / regular life)
Differentials: -2 (for reading, working at a desk, or using the computer)

Thank you @NottNott , this is a massive help.

Yes, get where you are are going with driving with differentials :see_no_evil:.

I haven’t quite figured out what prescription to get for my normalised, I went for an eye test last week and this has distorted my initial thinking slightly.

I ordered my differentials about a month ago, and spent a few months placing reading glasses over my regular glasses.

I have uploaded my recent prescriptions and would be very grateful if you or somebody else in the forum could check if my differentials that I ordered seemed reasonable in terms of my current full strength glasses that I wear (that are almost 10 years old) and what normalised prescription you would recommend based on what I am currently wearing and my latest eye test. @NottNott you mentioned to reduce by 0.25, but would you do that based on my current glasses prescription or my latest eye test result, what about the Cyc - leave alone at 0.75?

One last thing, in one of the videos, Jake recommends getting some contact lenses for distance vision (mainly for full peripheral vision, has everybody done this and do you recommend or is it to stick with your normalised? If contacts are needed, again help with the recommended prescription would be much appreciated

Thank you for all your help and support.

Jake recommends if your CYL is below -1, consider getting rid of it completely, set it to 0. Worked for me quite well.

I stopped wearing contacts the moment I found out about EM. Glasses are consistent and cheaper, and it’s already hard enough ordering correction for regular glasses. Contacts are 100% not necessary for improvement, I’m fairly certain Jake didn’t state that they are necessary for improvement.

Differentials seem fine, unless you’re working further from your monitor than 50cm. If you understand the math behind lenses you’ll be better off for the future:

Hopefully you’ve seen some noob fast gains. If the noob fast gains have stopped for you, your initial eye strain is gone. In that case, go 0.25 below your current norms for SPH and totally drop the CYL. Slow and steady wins the race with EM. Try not to reduce too quickly, but if you do that in the future just remember it’s really common.

There are a couple of non-EM things with your current glasses:

The cyl in your glasses are at different axes.
The axis of diffs and norms should be the same per eye. All through the journey. Currently you have a 10 degree difference in the right eye and a 20 degree difference in the left one. (180 = 0)
That in itself is enough to make you feel dizzy, fuzzy, off, seasick, etc.

The cyl in your differentials are higher than in your distance glasses.
As @NottNott mentioned, you could try dropping the cyl completely as you have less than -1D cyl.
If that doesn’t work then you should have the same cyl in both pairs of glasses (or if you choose to have different clys than the cyl should be lower in the diffs, not in the norms).


I’ll not go into asking the questions like “do you see 20/20 under almost any circumstances with the full prescription?” or “can you easily read street signs, ads, boards with the full prescription?” or “is the monitor at least 55cms away from you and still clear enough to read 12pt letters?”, etc

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Sorry for chiming in, but I’ve been reading the posts in this thread and this got me wondering if I got something wrong. I thought one should just drop the CYL (ofc only if it’s lower than -1, which it is in my case) in differentials but keep it in norms because it’s important for distance vision. Or does CYL have to be the same in diffs and norms? In that case, I would have to drop it in my norms too because my diffs with no CYL work quite well.

I also read that Jake said to tackle astigmatism after SPH. I’m at a similar point in my journey so maybe you could explain this to me. Thanks!

Edit: I just read @BiancaK 's reply which pretty much answered my question. So I guess I’ll drop the CYL in my norms too.

Thanks @BiancaK and @NottNott .

@BiancaK , given my current full strength prescription, using a 10m Snellen, I can see 20/20 at about 90%, is this an issue?

I am looking at replacing my current full strength prescription and they are very old. Would you recommend then that I keep the SPH the same at -4.25 and -3.75 - drop the CYL and leave the Axis at 0.

Following your comments, I think I will re-order my differentials at -2.25 and -1.75 dropping the CYL and leaving the Axis at 0?

Would I drop the CYL and Axis to 0 for normalised aswell then please?


@Shaf_K cyl can be tricky so you will have to accept a bit of try and error to figure out the first pair of glasses for diffs and norms.
But I would say dropping cyl from both is a good idea to test. Eliminates the differences in strength and axis. May take a while to get used to because you have been wearing cyl for quite a while. But if it works for you at the beginning of the EM journey it will make the rest of the journey so much easier.
If it doesn’t work out you can consider adding a bit of cyl back or a bit of sph. But I’d definitely try no cyl first.

I understand if this is slightly confusing.
Main idea is to simplify as much as possible with the first pair of diffs and first pair of norms. Not tackling diopters yet, just taking away the unnecessary overcorrections (cyl correction often proves to be unnecessary if the value is under -1D). After the first pairs, it is indeed first SPH then astigmatism.
It is simply because the cyl is also often overprescribed. It’s worth a try with the first pairs of glasses as this can reduce the complexity of the glasses a lot later.

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Thanks for your help @BiancaK

As the drop from full prescription to normalised initially is recommended at 0.25, would you still recommend purchasing a new pair of full prescription glasses, I am just thinking, having 3 pairs of glasses is going to be confusing.

Is it recommended to have 3 pairs or is the idea to replace your full prescription with normalised?


There are a lot of people who can get away in their everyday life without sharp vision - especially now with different levels of lockdowns in different countries. However, if you drive after sunset / before sunrise or your work involves situations where you have to see clear immediately (no option to wait until a blink clears up, no option to walk closer, no option to skip reading the departure board and look up the same info in an app, etc - in other words: there are professions less allowing for less vision, e.g. nobody wants emergency responders or surgeons to have less than sharp vision, hm?) then it is recommended to have a pair of fully full prescriptions. The legal driving limit in most countries is 20/40 which means you should be able to see very near 20/20 during the day especially outdoors, so you will still have better than 20/40 at night while driving in rain and or when you are tired.
The change in lighting conditions and your level of tiredness can easily add up to anything between a 0.25D to 1.00D vision “loss” from morning to evening.

Taking away the cyl will present a slight challenge especially at dawn and indoors in the evening, hence not recommending a drop with it as well. Alternatively if you are confident, drop 0.25D SPH, too.
Admittedly my approach is quite conservative on clarity. My preference was to see clear in my distance glasses, so I chose to wear norms that were very near the full prescription. Those gave me near 20/20 vision anytime and better than 20/20 in other situations (sunny days outdoors). I just made sure I wasn’t looking at anything close up with them on. If you use distance glasses for real distance vision time, you cannot ruin your eyesight by being overcorrected by 0.25D. You’ll just have a higher visual acuity level.

So to some it up:

  • all people need less corrections for close-up, especially for screen time or activities at closer distance than the arm’s length
  • all people need a correction for their everyday non-close up lifestyle. If that allows a little blur that can be a pair of norms. If that involves distance vision when sharp vision is needed it should be full correction or very near full correction
  • some people may have very different situations during the day. I.e. walking to the playground or to the school with the kids and later driving to work or driving in the evening. For them it is recommended to have 2 versions for distance glasses. Otherwise just wear norms and leave a pair of full corrections in the car and forget about them.

Just an additional thought to @marlensophie
I had an official opto measurement a month ago. I told the opto that I wasn’t wearing glasses and I told her I didn’t want to have a correction that is better than 20/20. She confirmed that I was OK to go without glasses most of the time (but recommended -0.5D for night driving in rain when I’m tired). And then she added that she measured a cyl every time at about the same axis, but she was unable to decide if that should be zero, -0.25D or -0.75D as every measurement ended differently. So this is behind starting with an initial cyl drop if your eyes allow.
Hope it will work out well for you, too.