Differential Diopters

Hi everyone, hope all is well :slight_smile:

I’m doing back to 20/20 program. I’ve reached the Differential Diopters section and I was wondering about something. I’ve lost my glasses almost 3 months ago and I just never got new ones. I’m comfortable without them as I believe I started using them less and less before I learnt about endmyopia. My question is can I continue the course without getting Differential correction glasses as I don’t wear glasses anymore? Thank you


Hi Ahmed,
I see in your profile that your stating point is quite low myopia and that your astigmatism is worse than your myopia. I don’t think you’d need differentials for the myopia part. So, I guess it all depends on your need for the cylinder correction… If you can read the text on your computer monitor well without any double vision / ghosting without glasses, you’re probably OK. But entirely dropping a -1,5 cylinder correction all at once seems a bit drastic to me. I personally got away with dropping a -1.0 cylinder, but as I understand it, that’s probably the outer limit.
As for not wearing any glasses at all: you risk getting blur adapteted. Maybe you already are…?
Anyway, if you’re in the Back to 20/20 program, you’ve paid for the support of the Eye Guru himself. So why not ask him?

If you paid for the official back to 20/20 program, click on the Support link in the second row between course list and Log tool (not on the Le Meow Forum in the first row of links) and write your question there. @jakey will get back to you within 24 hours typically.


Here in the forum you will get personal opinions only from fellow EMers.
Good people with good pieces of advices though based on their personal experiences. :relaxed:

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Thanks guys, I appreciate you took the time to respond to me :slightly_smiling_face:

Yeah, I thought they were the same forum haha. Cool, I’ll post my question there too, I feel like I know the answer to it but just checking :slightly_smiling_face:

Thanks again

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I’m also a Back to 20/20 student :slight_smile:

My take on your question:

Starting point (OD/OS): -0.75 -1.50 / -1.25 -1.50

If this is converted by an opto, it will be -1.50 and -2.00 by using the opto’s formula of 0.5D cyl = 0.25D sph

Going by the sph only conversion, you should be totally OK to go without differentials.

But! because of the high cyl compared to sph, it will be your personal experience that will determine if you can drop glasses for close up activities completely.
Your glasses have -1.5D extra correction added on the horizontal or vertical line (depending on your axis). If you have worn these glasses long and found them comfortable, got used to them then you may have got used to this uneven correction within each lens / eye. If you are seeing double without the glasses or if you get headaches without the glasses or if you don’t have double vision or headaches but you are not more than 45cms away from the screen, then it would make more sense to drop the cyl in steps (e.g. drop sph completely and keep some of the cyl). If you are perfectly happy and OK without corrections in front of the screen at a healthy distance (i.e. can utilise your peripheral vision, too), then there’s no need for corrections for close up.
As for glasses in general, to work away the last diopter I’d recommend wearing glasses for real distance vision time, i.e. when you are looking at distances greater than 10 metres. If you are going without corrections for the screen, then make the distance glasses without cyl. If you realise you need some cyl glasses for close up after all, then adjust the cyl in the distance glasses accordingly.
Reducing sph is mainly the work of the eyes, reducing cyl is 50% eyes and 50% brain - coordinating the overall image along the new and changed inputs from the eyes individually. (cyl causes an oval shaped distortion to the image, when you drop cyl completely the oval becomes a circle - that’s tough work for the brain to fine tune again)