Help for reducing differentials and normalized for high myope (-19)

Hi all. This is my first post after one year of following EM and also reading a ton and watching as much as I can of Jake’s videos. Despite all the warnings against asking about diopter reductions, per the Back to 20/20 “Strain Minimizer” post: “If you’re at all unsure after a bit of exploring, just start a new thread in the forum. Let me know your centimeter averages, your Snellen results and your current diopters. Include all the data so I can help you make a good assessment.” I am asking for help and advice. So please don’t yell at me since I am hoping this is the correct forum to ask this question. My answers to those questions are below:

1) Three days of centimeter averages for the left and right eye.
8.3 / 9.1
7.4 / 8.4
7.3 / 7.6
So my calculated diopters in general look like they should be around 13 OD and 12 OS.

2) Your Snellen results with your regular glasses. Glasses = 20/25 and 20/30; contacts = 20/20 both eyes.

3) Your current diopters (of your regular glasses). Glasses (sph/cyk/axis) = OD -19.25 / -0.25 / 175; OS -18 / -1 / 154. Contacts = (pwr / base curve / diameter) = OD -18.5 / 7.3 / 14.5; IS -18 / 7.3 / 14.5 (both also say “SC 8.6” and I can’t find what that means)

4) Your average comfortable ergonomic distance from your screen. With my contacts I can go as far as 110cm. With +2.5 readers with my contacts, I am comfortable at 50cm.

My summary, hoping for your feedback and advice: Based on the average of my measurements of distance to blur, my calculated average of diopters for both eyes should be around 13 and 12. Therefore, it would seem that my current “subscription” (-19.25 and -18) is WILDLY OFF and looks way overprescribed! So it would make you think that I could WAY down even for distance vision to maybe at least -15 or so for distance. But then with +2.5 readers while wearing my contacts, while I am comfortable at 50cm for reading at arm’s length, my distance feels really compromised (i.e., would not feel comfortable super comfortable driving). So that leave me a little puzzled, since the distance to blur calculations would put me at a much lower (negative, speaking in absolute terms) reading than just -16.75 and -15.5 (my prescription accounting for the +2.5 readers, which should be my calculated differentials) but the distance vision with those readers, and even +1.5 readers!) seems quite intolerable for anything except near work.

So would your recommendation be to just get new glasses made for -16.75 and -15.5 for near/ computer work, and leave my normalized (even if my normalized seems overprescribed)?

Two other pieces of potentially relevant information: a) I do have astigmatism (which began last year) so my distance to seeing clearly is just around 6mm, so per Jake’s astigmatism post, my “range” of seeing clearly without lenses is basically just 1-2mm. b) I get my glasses made in Hong Kong because they allow higher refraction there and my prescription, if made with US lenses, is impossibly bulky and the thickness of the actual lenses actually distorts my vision. They aren’t cheap to make, which means I’m trying to be somewhat economical about getting numerous pairs made, but again, it’s for my eye health and willing to do what it takes. The other option would be just to use my contact lenses and get readers for near work, which is cheaper, but I’m simultaneously also trying to have less plastic in my eye for the entire day if possible (even if they are rigid gas permeable lenses with a soft skirt, since especially the soft lens part decreases oxygen significantly to my eyeball). c) I have found a GREAT optometrist in San Francisco who is willing to basically allow me to dictate what prescriptions I want for my contacts and glasses. My vision plan covers me for 1 set of contacts for the year. I am due for new contacts now, and can’t get them covered under insurance again until another year. Given this, would you suggest I ask him for a decreased contact lens prescription of maybe about -1 diopter since it seems like I’m overprescribed and try decreasing my normalized prescription first, and then going to order the glasses (which I pay out of pocket for), and in the meantime, use readers for near-work? I know the idea is not to try to reduce both at the same time, so maybe not use readers for near work for 6-8 weeks, and then after my eyes are adjusted to the decreased normalized prescription for distance to try to get the differentials at that point?

Thank you in advance for reading this ultra-long post and any advice you can provide.


If you’re wearing store-bought readers over your contacts those could introduce a lot of distortion and prism that could be messing up your distance vision, so it’s not necessarily a good indication of what your distance vision would look like with a lower powered contact.

Is it expensive to get additional contacts made if you paid out of pocket? If it’s affordable, I think I’d get some -14 contacts and then see what you can actually see out of them, and maybe try cheap-to-make distance glasses over your contacts. You might be able to use the contacts for near work and then wear a pair of -2 or -4 glasses over them for driving (whatever gets you to full correction). If you’re really at -18 and not over-prescribed you could keep using higher powered contacts for now, or wear reading glasses over the -14’s for close up.

It sounds like economically it might make sense to have the contacts do the “heavy lifting” and use cheaper glasses over them for fine tuning, since the very-high-powered glasses are a specialty item.

If you do end up using plus lenses over contacts, I think you’d be much better off having some made up for you (cheaply) at one of the online retailers using your correct PD.

If there’s a real chance you’re severely over-prescribed that’s very scary, you don’t want overprescription to make things worse. Did you start out much lower and then go up every year (lens-induced?)

Thank you for your thoughts. That’s interesting that store-bought readers could introduce that much distortion to mess up the distance vision, and to think about how that may not be the best way to test out a potentially lowered contact lens prescription. I can’t imagine going that low but I guess I won’t know until I actually try. It’s a good idea to use the contacts and cheaper Zenni-type negatives to bring me up to my distance-required activities, as it’s more economical, although for swimming (my main form of exercise) is easier sans glasses, and it still keeps plastic on my eyeballs 18 out of 24 hours, so trying to use more glasses in general if possible. I know I can’t have it all and trying to figure out the best way to increase my eye health (I have been diagnosed with myopic degeneration which is another stimulus for doing the 20/20 program).

To answer your question, I don’t think I ever had a huge jump in my prescription (“subscriptions”). When I started wearing glasses at age 5, they were already quite thick, although I don’t know the exact number, and I imagine I was getting 0.5 to 1 diopter increase every year, which finally “stabilized” in late 20s to around what it is now…

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I understand what you’re saying about not wanting plastic on your eyes all the time.

Probably the first thing to tackle is to make sure you’re not severely over-corrected right now. I’m concerned that your own cm measurements got you to a much smaller amount of correction than your current “subscription”.

It’s kind of “uncharted territory” and outside of “EndMyopia” but since you’re already off the beaten path and you’re in “high risk” territory given your high myopia, you might also consider using low-level red light and some of the lutein, zeaxanthin, and astaxanthin supplements given that your eyes could probably use all the help they can get. You’ve already got the medical background to assess the potential risks and benefits. My take on them is that they’re possibly helpful, certainly not proven, maybe worth a try. I think astaxanthin is “generally regarded as safe” in the USA.

Maybe something useful for you in these…

Nakamura A, Isobe A, Otaka Y, et al. Changes in visual function following peroral astaxanthin. Jpn J Clin Ophthalmol 2004;58:1051-1054.

Collection of papers on astaxanthin:

“In several Japanese RCTs, astaxanthin improved visual acuity and eye accommodation.” Summary from alternative medicine journal. :woman_shrugging:

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It’s difficult to measure accurately at this myopia degree.

Potential start would be to just drop 1.50 diopters and experiment with that as first differentials. They’ll also be easier to measure centimeters with (just add the distance equivalent).

That could be contact lenses, also. Various options here for a start.

If you’re doing the course, most effective really is to start with differentials and not mess with distance vision for now. You don’t want to change two focal planes at once, and the ‘problematic’ one is the current use of distance for close-up.

It’s also vastly easier to get used to reduced diopters in a controlled environment (single distance, consistent lighting, etc). Find active focus, do so some measuring, have the experiment - all while your distance vision is exactly as always, you’re not taking any chances with driving, work, all the things that require reliable vision across the range.


Thank you so much for sending these very helpful links! I will educate myself on them! Thank you!

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Thank you very much, Jake. I will work on the differentials first as you suggest since it is true that the more problematic one is using distance for close-up work! Grateful for your input!


The references you mention suggest that you follow the official back to 20/20 program. Click on Support 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. Jake will get back to you within 24 hours typically.


He got back to you here, too, but this is not typical on this forum at all.
Here in the forum 99.9% of the time you will get personal opinions from fellow EMers. Often good ideas though.

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Yay thanks for catching this!

Thank you so much for taking the time to point this out and even provide a screenshot! I’m sorry it took me so long to thank you for this. I’m grateful!