Optician warns about differentials...many questions

Maybe an odd thing to ask, but I googled and searched the forum but didn’t find this issue:

I wanted to get differentials from an optician. So first she refused, then I told her I get headaches and strain around my eyes when I use my full prescription and will have to do lots of close-up work in the next months. She then told me that a) I am too young for “reading glasses”, my eye should be able to handle the change of focal plane, b) If she gave me reduces lenses now I would have problems when I get older and really need them because I would need even stronger reading glasses.

I didn’t get what she was trying to explain to me. As far as I am aware of reading glasses for old age have to do with the hardening of the lens. Has anybody come across an optomologist saying this or know what she might mean?

Thanks a lot in advance,


This is a new one to me. I am afraid that if you want to go the EM way, you will have to take what opto’s tell you with a pinch of salt.
If this is worth anything, I am a 75-year old myope who does not need reading glasses. Because my myopia was not that high (-3 in the right eye that does all the work), I was able to work at screen distance for the past 30 years without glasses, so you could call this fairly strong undercorrection for screen distance, which could be equated with wearing differentials. This was probably not ideal and I am more comfortable at the screen now with an uncorrected -1 right eye. But it did not lead to the need for reading glasses, let alone stronger ones…

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She might have thought that you are asking for plus lenses as it is not common for people to ask for differentials and most optometrists have not heard of the concept at all. You could try again with another optometrist or order online. With only reduced minus lenses for close up, there shouldn’t be any issues if you choose approximately the right ones, let alone long term damage later on.


Thanks for your answers. She was fully aware that I only wanted weaker minus glasses. It was quite odd… here colleague in the store had told me a week prior that it is no problem if I want a pair of reduced lenses and they would be happy to sell me some. I should just make an appointment so they could to fit me with a pair. I then told the uncooperative one (I then had the appointment with) about that colleague - and it just confused her even more. It was quite an uncomfortable situation.

She did sell me ones that are reduced by 0.75 in the end - and put an antistigmatism of -0.25 in it - which makes me wanna throw up (sorry for the language, but it is terrible and makes me dizzy). I am going to send them back and order a pair online.


Reduction of 0.75 is too strong for diffs and too weak for norms. The one study I saw showing reduced lens therapy causing progression was with +0.75. I wouldn’t wear those unless you have an atypical medium distance task.


Good idea. It is very hard not to be talked into something you don’t want when in the hands of the ‘professionals’. I have had no problem with this with the eye professionals, but with other doctors I have had many an unpleasant battle. The upshot of this is that I no longer consult any doctors.


Thanks! Yeah, I am not going to use them. They have a 100 day return policy I am going to make use of. Can just chuck them in the post and they go on their merry way back to the factory…

Yes, it was really annoying. Now nobody has what they want. They don’t have a sale and I don’t have the glasses… She was “just” an optician though, no doctor. Sorry I got confused with the linguo there in English :wink: I’ll change the description in the title.

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Yes, same story here ! It’s interesting I found your post. Instead of answers, I’ll bring my story and some details, and also add questions, because I feel there weren’t enough answers to this subject :wink:

So for a bit of context, I went back to the optician where I had my first pair, for a 2nd one, 6 months later. I found I had not much improvement and thought I might have been reducing too much at once.

The optician asked me, as they all do, why did I ordered 2 pairs of glasses (normalized and differential) instead of one. “You are young, you can accomodate! You don’t need two pairs of glasses. Instead you’ll have bifocals when old. You’ll get there eventually, like we all do.”
This time she seemed to want to scare me out and she really insisted that I should wear my normalized ALL TIME. Even on the computer, and that I should stop wearing my differential now because it would worsen my myopia. She made a little simplistic drawing to explain to me how it worked, saying that me eyes, when reading on a screen, would have to accomodate 2 times more than if I wore my full correction! I discussed a lot with her, with what I learnt and knew of cilliary spasm, optics and everything, but she confused me.

She forced me into promising to stop wearing differential if I wanted a new pair, and wear only this one. She told me she risked her diploma and I risked my health! Well, I tought it’s more about my eye health than your diploma, as I’m not returning to see you after that.

We did the eye test (she required it, I couldn’t just tell her what subscription I wanted) and then, as I asked a lot of questions on what she did (to be sure of what I would guet in the end), she told me “You see, it’s there that your patient role ends and my role begins”. I almost told her I was rather her client but well.

Anyway, at the end I got more or less I wanted, that is an augmentation of 0.25 of my latest subscription so that AF would be easier, more efficient and headaches-free. BUT, she changed my focal plane from 0.50 to 0.75, by giving more to my weaker eye, because I “needed it”. I couldn’t say anything more to get what I wanted at the end of this one hour struggle. So I said okay, let’s do it.

Do you understand what she had in mind when trying to explain me what she did ? She quite confused me. She was saying I could adapt because I was young but at the same time I shouldn’t adapt by changing lenses everytime. She seemed to contradict herself. She still agreed at the end I had a great adaptation capacity (she put 5 for the prism instead of 2 for the average people, until I “could see double”).

And do you think this change of focal plane will affect my gains and is this a big mistake, increasing gap with weaker eye, or would it have minor incidence on the progression ? I plan to test and possibly do patching to try equalizing a bit the weaker eye. I intend to wear this pair only I few weeks before passing on the precedent one, expecting gains to be at the rdv. I hope I’m not wrong.

Sorry, this was a bit long, but I’m curious to know your thoughts and knowledge about this :slight_smile:


Oh no I’m so sorry that you dealt with this, it seems like an awful experience.
Honestly I would not take seriously what a rude optometrist thinks is necessary for me. She says that you won’t have to accommodate up close with normalized? Unless she means the exact opposite (that is, “your ciliary muscle won’t have to relax at all”) she’s just gaslighting you. I mean regardless of what she meant, she’s gaslighting you.

I don’t see the point of creating a wider diopter gap: as long as your eyes are both working on clearing the blur then you don’t need to add any more difference between them. How did she even determine that you “needed” the additional -.25 in the “weaker” eye? Autorefractor? Or just messing around with lenses? Anyway you only “need” a higher correction in your non-dominant eye if it’s not improving and your dominant eye is doing all the work.
In my case my eyes are working well together and improving at the same rate, so when the autorefractor wanted to give me -.25D more in the left eye I just kept wearing equalized lenses because? I don’t see the point of correcting my left eye more if it’s not giving up on the blur?


Thank you for your answer !

Wow, I didn’t know about that gaslighting notion. I feel like optometrists and opticians always do that. Effectively, she didn’t make any sense with what she said. At the moment, I couldn’t make a clear argument to fight back so I pushed her to make sense by asking oriented questions but that wasn’t really successful.

For the wider diopter gap, she determined it by messing around with lenses, ahah. When she told me “I’m gonna see if you have a dominant eye”, I was quite expecting that at the end… But I couldn’t order anything else sadly. Next time I’ll buy on the internet.

In the end I don’t know what to do with this new pair. I don’t know if I’ll ever wear it… I fear it may weaker my weaker eye even more. It is improving as well as the other one indeed.
One thing I’m telling me is that here I’m going the way down instead of up, so maybe it’s not that severe to increase the gap (as if I’d put older glasses). When I move back to the lighter subscription pair the gap will be reduced again.

I don’t think it’s gaslighting. They learnt that what they are doing is “The Truth”, “The Way”. They never had to question it, or even really dig into the “why” behind what they are doing. They received a ready recipe to apply to everyone. They react badly when they are questioned about their truth, especially when they feel attacked, realising that there may be something in what you are saying. What you see from the average opto (feeling attacked => responding with attack or threat emphasising authority) is normal human behaviour. The only issue is that it’s your eyes concerned…

If I were you, I wouldn’t introduce the 0.25D difference to my vision. Eyes would be OK, but the brain’s image processing changes by unequal corrections adding complexity to the journey back to 20/20.
Equalising is a slow and tricky step as you can read from many on this forum.


Yes, I agree. They feel like you’re challenging they professional authority and their knowledge, result of years of learning. It must not feel good. (Of course our interactions stayed into the friendly range, but yeah that’s what can be felt beneath.)

Yes, I calculated again with my vision measurement tracking and realized my left eye wouldn’t make any effort anymore with this new subscription. One thing I thought is that I could remove the weaker eye lense of the new pair, and put the other one in it (it’s the same frame) : it would change the focal plane again, but I’d be going toward equalizing. (from 0.50 to 0.25 gap, instead of going to 0.75).

But anyway, this led me to realize I don’t really need this correction anymore, as I’m making more progress than I thought. Surprisingly, doing her eye tests seem to have contributed training my eyes to even better adaptation and AF! :woman_shrugging:

Also, she told me that for them, it didn’t matter the distance to which you were looking ; rather, it was the clarity that mattered. From 5 meters, or even 2m, it was considered as infinite. Of course when you can’t see at more than 30cm without lenses, it seems obvious, but with lenses, I didn’t get it : if you can see everything well from 5 meters with them, it doesn’t mean you’ll see as well on the highway at 100m. And then she made test me from 150m to adjust clarity.

Any thoughts on this ? Maybe it’s very basic but I’ve never been good at math.

huh, that is odd. I do not get it… The optician usually sells glasses that are optimized for maximal distance - ok. But why should this distance “not matter”? If the optician were to give me glasses based on me holding a pamphlet in my hand I would leave with totally different diopters than looking at a 6 feet chart.
I can read fine with my diffs, although I cannot read street signs - as I understand that is because the glass does not break the light enough for it to hit my retina correctly. For objects that are closer (eg, this screen right now) the refraction power of the glass is strong enough for it to reach my retina (because the light breaks on an object that is closer to me). At least that is my understanding of optics…


or did the optician refer to astigamtism? Not sure if the distance matters then.

Hmm… why? The glass breaks the light… the ciliarly does not have to tense up a strong if the light is broken according to the distance… where is the problem? Odd…

I have come to think that the endmyopia concept (and the “science”/discussion about growing prevalence of myopia behind it) is a different approach at thinking about myopia all together. If you follow the idea that prolonged hyperopic defocus causes and/or worsens myopia and distance to blur is central for this not to happen (as is discussed in current medical textbooks) - then one cannot wear full correction. Whether this has some kind of effect on the lens of the eye and its ability to accommodate - that is another story. According to this forum it does not seem to be anything to worry about. I personally think that if you make gains using the endmyopia method and your eyes are actually becoming progressively less myopic, then a “fear of looming presbyopia” would take a back seat for me.
On another note: A while ago I was searching different forums abour eyesight/health and did read about people here and there using their old glasses for extended periods of close up and noticing that they myopia had stopped increasing. Of course they could not say if that was pure coincedence (and rather realted to ageing) or not. One of the first things I noticed when starting with diffs was that I had basically gotten rid of quite a strong accommodative lag I had developed (not being able to see things in the distance clearly for quite a while after e.g. reading something on my phone for some time). I mean - that has stopped happening. I reckon that is a good thing :wink:

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Someone is really confused. That is not how that works at all.

The scale is logarithmic, so 4 m is a quarter diopter off from infinity. but street signs and other practical focus targets are closer than infinity, so 4m is plenty sufficient to get a slightly under corrected for practical distances. 2m is a half diopter off from infinity. That’s starting to get a bit too close for getting your maximum distance vision out of a test, but if you want to be slightly under corrected it works in your favor.

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No she wasn’t referring to astigmatism.

Thanks for sharing your thoughts.
Yes this story of accomodation “scared” me a little, because I never really thought of it before. While reading about Endmyopia and people’s experiences, I never heard of problems of that sort. Maybe the time gap since the creation of Endmyopia and the beginning of people starting gains isn’t enough for now to tell if this method has an effect on accomodation. Or maybe the fact that nobody discuss it means the problem hasn’t occured (10 years, at least for Jake, I think is beginning to be quite consistant to notice this sort of things).

But yes, I definitely would go on trying the method if I noticed positive changes (which is the case). That’s true also I got rid of that accommodative lag. I hadn’t noticed, but now you talk about it I realized I was wondering these days why I hadn’t this lag anymore (I attributed it to better habits).