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Glasses Over Contacts (GOC)

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rollin 17 Dec 2017, 00:34

Want GOC for night driving. Don't want to remove contacts in the car.

Multifocal contacts Rx is

R +2 +2 N

L +2 +1.5 D

Driving vision is perfect when I wear +1 readers with no contacts.

I am guessing it might be -1 -1 glasses over the multifocals, what do y'all think? Eye doctor has dragged his feet on this, could use some advice about next steps.

JC 11 Dec 2017, 18:58

Anonymous user: If your are in the U.S. or Canada I would recommend

 11 Dec 2017, 18:28

where can i buy contact lenses without a prescription online? please help.

Soundmanpt 27 Nov 2017, 11:10


To be honest I didn't recall our previous comments from last year until you reminded me. You always admired your husband's strong glasses and wished that your glasses were as strong. You were excited to here about GOC as an option and with the help of Cactus Jack in figuring out the proper combination for for contacts and glasses for your eyes you were soon wearing GOC as a full time option and loving it. It only took a short time for your eyes to fully adjust to your new GOC vision and you were seeing even better than you ere with your actual prescribed glasses. Wearing stronger glasses has had a other effects on you as well. You're now much more self confident and self assured. Wearing stronger glasses has made you a stronger woman. One of you first comments I found very interesting.You said "I now feel and look as though I need glasses" Interesting because you had already been wearing glasses for many years.

I remember you had a friend that after seeing you wearing your stronger glasses was so impressed that she wanted to do GOC too. You said her actual prescription was around -1.50. Did she ever start doing GOC? If so how is she doing?

I don't know what prescription Zenni will make myodisk lenses at. Zenni has a open chat line. I would suggest making up a story about a friend that wears myodisk glasses and you really like how they look and your just curious at what prescription is where myodisk is used.

anonymous oo 27 Nov 2017, 02:11

The axis should be also 80° if you write the cyl for the glasses with +

You could also write(for the glasses)

+5,5 cyl -4,5 axis 170° (80+90)

The effets of the Vertex distance are not really strong in this range, so it would probably be quite accurate...

but I prefer to find out the proper glasses prescription with my trial lenses, not only by calculation

JohnnyB 25 Nov 2017, 12:00

So if you have 20/20 and wear a contat of -1 -4.50 x 80, what should the compensating glasses be? +1 +4.50 x 120?

anonymous oo 25 Nov 2017, 03:29

For inspiration only!

Hello there,

yes, I am an OO and I sometimes post to this forum under a different name.

Today I want to share my latest goc experience(experiment)

I am experienced with both +and - Glasses Combinations...

My natural Vision is almost perfect...does not need much correction...but I dont have stereoscopic vision(Distance RX: L +1 R+-0)

The advantage(;-)) is that in my case PD does not make a big difference, I can use Random second hand glasses, for example from MS.(Glasses for auktion...thread)

This week I got a pack of toric contacts(out of curiosity)Proclear Toric XR (I already like Procear-spheric-very much and know I can handle them) in +0.5 cyl -4,25 A 90°.

They are stablized by a so called prism ballast, so they are more heavy at the bottom to get the axis correct.

So if for example you lie down on your side the axis changes by about 90°.

This effect is very funny, because if you wear this lenses in combination with glasses that compensate your vision to normal everything gets extremly blurry when the axis is 90° wrong, the cyl of the contacts and the glasses add to each other and simulate an astigmatism of more than 8 diops what very very seldom occurs in nature.

If you get horizontal and make certain moves, the effect is even more crazy...the contacts start to rotate and the vision changes from nearly perfect to complete astigmatic blur all the time.(Stars change to stripes and back ;-) )

I tried all of this today with my trial lens set and cant wait to get the real glasses.

Yes, I am an astigmaphil as well, but I am not the Person useing that name.

rafa 21 Nov 2017, 02:16


Don't worry about requesting a different prescription, it won't flag anything at Zenni's.

I myself have ordered various different prescriptions from them and they have never asked any questions.

Sarah 20 Nov 2017, 15:28

Would the index of lens I choose from Zenni make a difference on the myodisc effect to them?

Should I make a special request to them? They don't offer a myodisc option - how would I word that?

I do order from them for my regular glasses and have quite the collection, I hope it won't flag anything and make them ask for a copy of a prescription to suddenly order such a stronger rx?

30calcat 20 Nov 2017, 12:55

Zenni's lens blanks are pretty thin so if you order a big enough frame they will come back with some myodisc effect, even in -10. I had a 53/19 frame come back with the non-powered part of the edge beveled into a frosted zone.

Juliette, the clearer vision you are getting with GOC may be due to the increase in depth of field from the stronger minus lenses.

Billy A 20 Nov 2017, 06:43


Hi, I have myodiscs for GOC with -14 (by Essilor), optician said thats possible to make it from -9 and "are reccommended from -15, but lower will be fine too and I can say more comfortable, because the active zone will be larger"

It depends on where you are located. In the Europe this is not problem.

juliette 20 Nov 2017, 01:13

Soundmanpt, You may remember that I started GOC about a year ago with advice from this website. Yes, I had been wearing glasses or lenses for many years, but with a modest plus prescription. I started at -9.00, & now at -12.00 with little or no problems. I use the combination of lenses/ glasses daily. Its great, & somewhat addictive, & as I have said previously, I & my husband like the way I look. I find that my vision is much more clear & crisp with the GOC combo than with my 'True' glasses. How is that possible?

The small amount of minification has not proved to be a problem for me. As I said in a previous post, & like Sarah I would just like to try a pair of Myodiscs, just to see what they are like to wear, but I don't think -12.00 is enough yet to get myodiscs.

 18 Nov 2017, 17:16

Thanks Soundmanapt.

I wonder what the lowest Rx Zenni would make myodiscs at?

I don't want to go too crazy high like -18, I want to be able to wear them, I also don't want my eyes to be quite so minimized and hidden in the rings

Soundmanpt 18 Nov 2017, 09:41


Were you already a glasses wearer when you started doing GOC or did you start doing GOC so you could start wearing glasses?

Cactus Jack 18 Nov 2017, 09:39


If you want to do GOC, I urge you to learn how to do the calculations, they are not very difficult, I also urge you to try a GOC combination around -10 before working up to higher glasses values.

The thing that primarily affect the GOC powers is Vertex Distance effects. It is the mathematical Square of the glasses prescription. It has little effect below about -4.50, but becomes very significant above about -10 as you will see with the following calculations.

Sphere and Cylinder calculations are done separately, but your Cylinder correction is so low, all you have to do is transfer the Cylinder and Axis to the glasses prescription WITHOUT any changes.

Vertex Distance (VD) effects of Sphere -15

-15 x -15 = 225 (note that the sign is now +, but don't worry about that, all we want is the absolute value.

Next divide by 1000

225/1000 = 0.225 That is the VD effect. 0.225 diopters per mm

Next, multiply by the distance from the front surface of the cornea to the back of the glasses, this is the Vertex Distance. It is very hard to measure accurately, but typically is is 10 to 12 mm. Lets assume 12.

Total VD effect

0.225 x 12 = 2.70 diopters.

What to do with that number is a bit tricky. It depends on whether the glasses have - lenses or + lenses. In your case with - lenses, you SUBTRACT the 2.70 from the -15 to determine the effective optical power of the -15 glasses at the Cornea.

-15.00 minus 2.70 = -12.30 That is the calculated power of the -15.00 lenses at your Cornea. If your prescription was 0.00 You would need +12.00 Contact Lenses. The reason for +12.00 is that you can only buy high power contact in 0.50 increments and it is best to use contacts that are a little less plus than you need so your Ciliary Muscles can add a bit of extra PLUS to compensate, assuming you still have some accommodation left.

Now we need to adjust the CL power for your actual refractive error and that can affect the choices you have.

You posted the following actual prescription:

L -5.00 0.25 18

R -4.75 0.75 085

Ignore the Cylinder and Axis for now.

Remember, normal Glasses or Contact prescriptions Neutralize or Cancel Out your actual refractive error. That means that your ACTUAL Sphere Refractive Error is:

L +4.75

R +4.50

Adjusted for VD effects and rounded to nearest power availability.

You have a built in, head start on the Plus CL prescription for -15 glasses. The required contacts would be:

L +12.00 minus +4.75 = +7.25

R +12.00 minus +4.50 = +7.50

I think I would use +7.25 or +7.00 CLs in both eyes and let my ciliary muscles compensate. An alternative would be to slightly adjust the Sphere prescription in the glasses.

Using the above as a template you can do the calculations for any desired glasses prescription.

I don't know at what prescription Myodiscs become necessary, but I believe it is around -18 to -20 using CR-39.

Please remember that GOC is NOT an exact science and is highly sensitive to VD effects.


juliette 18 Nov 2017, 01:44

Hi Sarah,

It sounds as though you want your glasses looking stronger by using GOC as they call it. I am the same, & since about this time last year, I have managed to get to -12 with very few problems. I like it very much, & how I look. I too would like to try some myodisc lenses to see what its like, & how I look in them. Wish you success with your venture, & please keep us posted if you get myodiscs.

Sarah 16 Nov 2017, 17:06

Been reading s while, new to posting. Lots of questions?

My real Rx is

L -5.00 0.25 18

R -4.75 0.75 085

and -5 both eyes in contacts.

I'm curious both what Rx plus contacts I'd need to try wearing -15 or -16 glasses. Also curious to try myodiscs. What is the lowest Rx those are typically made for?

I also sometimes wear as much as -2 overcorrection in glasses, wonder how much more I could tolerate. I'm 31 and don't do a ton of close work.

Soundmanpt 28 Sep 2017, 08:07


I would agree with "rafa" and depending where you live you might even wnt to call them and ask at what prescription you can have have your glasses made with myodisk lenses? Or use the "comment" box to request myodisk lenses.

rafa 28 Sep 2017, 02:36


I got myself a pair of myodisc glasses from Zenni. They are minus 20, which is as high as they make them at Zenni.

I actually didn't want myodisc lenses but since I order the thickest lenses (as I like them), It turns out that they only fill that sort of prescription on regular lenses with myodiscs. I'm very happy with them now.

So my guess is that if you go for really high prescriptions, Zenni might be able to do myodiscs for you. But it's best to ask them first.

juliette 06 Sep 2017, 00:59

I have posted a few times to this site. My venture with GOC has gone well. Can anyone advise where I can purchase 'Good' quality myodisc glasses? Suggestions would be appreciated

 24 Aug 2017, 08:39

Hi, probably a little off topic, but I couldn't find a more suitable thread to ask this. I would like to know if someone has experience with sclera lenses for keratoconus/dry eyes? Or does anyone know where to get them in Europe? I'm curious and would like to try it.

JC 05 Aug 2017, 15:26


I see what you mean. With your family's interest in glasses and your history of moving to a very low prescription I can see the danger in showing up with a significant prescription one day. I suppose I'm lucky nobody in my family has a special interest in glasses and they all know I am a full time wearer. And of course I'm lucky my wife knows about and accepts GOC.

While I don't make any effort to avoid wearing any particular glasses in front of them I do avoid any situation where I might have to remove them in front of them. My sister in particular knows my prescription is the same as hers as several years ago she needed to borrow a disposable lens from me. It would be awkward if she suddenly saw me with much worse vision then herself.

Maxim 05 Aug 2017, 04:25

PS to JC:

After the OP, I have not only the two varifocals (bought one month and 8 months after OP, not satisfied with the concept, always blurry zones) but as well:

1 pair bifocals PC and near vision (that is +1.25/+2.75 against distance vision) - bought them 2 weeks after OP -

1 pair bifocals distance and near vision (o.oo / + 2.75) - superb from Zenni, at a total price of 40,00 $ approx., 20,00 the frame, less than 20,00 $ the bifocal lenses with antireflex - superb quality and vision !! bought 4 months after OP

1 pair for distance vision, sunlight absorption 80 per cent, brown, for driving - bought them 2 weeks after OP -

Maxim 05 Aug 2017, 04:16

to JC:

Thank you very much for your friendly remarks and comments.

My real prescription was until May/June of 2016:

R + 4.00 / - 1.75 cyl A 85 degrees,

L + 3.25 / - 1.25 cyl A 110 degrees

with an add of 2.00 or 2.25 etc.

In early summer of 2016 I had the cataract OP, and I paid for the state-of-the-art measurement, and so, after the cataract OP (I did not pay for tailored-to-measure IOLs), only the astigmatism is more or less uncorrrected.

My new prescription is (slightly modified over the months, and slightly different in three different shops - I have an appointment for 'objective' measurement):

R + 0.50 / - 2.00 A 103 degrees, and

L - 0.50 / -0.50 A 102 degrees, and, of course, an add for near vision.

This is really near nothing (especially in the left eye), but however, I enjoy wearing glasses, because there is more sharpness in the image. An example only: a car registration plate on 50 yards/meters: without glasses left eye blurred, right eye nothing or totally in blur.

With glasses: can read the registration plate, left eye superb, right eye, fairly good. Why should I NOT wear glasses??? I prefer seeing WITH glasses!

All of my family are glasses lovers and glasses experts of their own. My wife wished desperately to wear glasses, when she was young and did not really need them. She loved her children wearing glasses, and me as well. Everybody is trying the other's glasses, and everybody in the family knows about the other family members' prescriptions.

When I first had new glasses affter the cataract OP, I told my son (now 31 yrs) that my prescription now was near to nothing, and he took my glasses, looked through them and then confirmed, what I had said.

So, quite frankly, do you agree, that they might be on the alert, if I would show up with my -5.00 prescription glasses over CLs?

By the way, before the OP, I wore -8.00 over +5.00 CLs. And now, my +6.00 glasses are a pair of reading glasses, when my eye was at +4.00 etc before the OP. These are the only glasses, were they don't ask - I can also use glasses before the OP (+4.00 etc) from before the OP as readers, but they are for very, very close vision now!

I'm planning for some nice Zenni bifocals with -7.50 etc, as +8.00 CLs are the maximum power to buy at reasonable prices (30-40 cent each) as throw-away lenses from , but I am also planning for more glasses around my real prescription (variation in power, cylinder, a bit of prism etc., and bifocals for distance and near, bifocals for PC screen and near - this is very important -). I have two pairs of varifocals now, but I really don't like them, everything is moving uncontrollable, and they irritate me when driving.

I feel better for driving with a -5.00 GOC-combination, than with varifocals in my real prescription!!

The best wishes and greetings,


rimpopper 04 Aug 2017, 15:42

Sallust: The advice you're getting is solid. Here is the information from my spreadsheet for someone with emmetropic eyes:

For emmetropic (normal) eyes here are the required eyeglass refractions; as you can see, VD does not matter until you get to +10 and beyond; calculations for +2, +10 and +20 contacts are included.

+2 contact .012 VD -2.05 (-2.00) -2 / (1 + (.012 x -2)) = -2.05

+2 contact .013 VD -2.05 (-2.00) -2 / (1 + (.013 x -2)) = -2.05

+2 contact .014 VD -2.06 (-2.00) -2 / (1 + (.014 x -2)) = -2.06

+3 contact .012 VD -3.11 (-3.00)

+3 contact .013 VD -3.12 (-3.00)

+3 contact .014 VD -3.13 (-3.00)

+4 contact .012 VD -4.20 (-4.25)

+4 contact .013 VD -4.22 (-4.25)

+4 contact .014 VD -4.24 (-4.25)

+5 contact .012 VD -5.32 (-5.25)

+5 contact .013 VD -5.35 (-5.25)

+5 contact .014 VD -5.38 (-5.25)

+6 contact .012 VD -6.47 (-6.50)

+6 contact .013 VD -6.51 (-6.50)

+6 contact .014 VD -6.55 (-6.50)

+7 contact .012 VD -7.64 (-7.75)

+7 contact .013 VD -7.70 (-7.75)

+7 contact .014 VD -7.76 (-7.75)

+8 contact .012 VD -8.85 (-8.75)

+8 contact .013 VD -8.93 (-9.00)

+8 contact .014 VD -9.01 (-9.00)

+9 contact .012 VD -10.09 (-10.00)

+9 contact .013 VD -10.19 (-10.25)

+9 contact .014 VD -10.30 (-10.25)

+10 contact .012 VD -11.36 (-11.25) -10 / (1 + (.012 x -10)) = -11.36

+10 contact .013 VD -11.49 (-11.50) -10 / (1 + (.013 x -10)) = -11.49

+10 contact .014 VD -11.66 (-11.75) -10 / (1 + (.014 x -10)) = -11.66

+11 contact .012 VD -12.67 (-12.75)

+11 contact .013 VD -12.84 (-12.75)

+11 contact .014 VD -13.00 (-13.00)

+12 contact .012 VD -14.02 (-14.00)

+12 contact .013 VD -14.22 (-14.25)

+12 contact .014 VD -14.42 (-14.50)

+13 contact .012 VD -15.40 (-15.50)

+13 contact .013 VD -15.64 (-15.75)

+13 contact .014 VD -15.89 (-16.00)

+14 contact .012 VD -16.83 (-16.75)

+14 contact .013 VD -17.11 (-17.00)

+14 contact .014 VD -17.41 (-17.50)

+15 contact .012 VD -18.29 (-18.25)

+15 contact .013 VD -18.63 (-18.75)

+15 contact .014 VD -18.99 (-19.00)

+16 contact .012 VD -19.80 (-19.75)

+16 contact .013 VD -20.20 (-20.25)

+16 contact .014 VD -20.62 (-20.50)

+17 contact .012 VD -21.36 (-21.25)

+17 contact .013 VD -21.82 (-21.75)

+17 contact .014 VD -22.31 (-22.25)

+18 contact .012 VD -22.96 (-23.00)

+18 contact .013 VD -23.50 (-23.50)

+18 contact .014 VD -24.06 (-24.00)

+19 contact .012 VD -24.61 (-24.50)

+19 contact .013 VD -25.23 (-25.25)

+19 contact .014 VD -25.89 (-26.00)

+20 contact .012 VD -26.32 (-26.25) -20 / (1 + (.012 x- 20)) = -26.32

+20 contact .013 VD -27.03 (-27.00) -20 / (1 + (.013 x -20)) = -27.03

+20 contact .014 VD -27.78 (-27.75) -20 / (1 + (.014 x -20)) = -27.78

+21 contact .012 VD -28.07 (-28.00)

+21 contact .013 VD -28.88 (-29.00)

+21 contact .014 VD -29.75 (-29.75)

+22 contact .012 VD -29.89 (-30.00)

+22 contact .013 VD -30.81 (-30.75)

+22 contact .014 VD -31.79 (-31.75)

+23 contact .012 VD -31.77 (-31.75)

+23 contact .013 VD -32.81 (-32.75)

+23 contact .014 VD -33.92 (-34.00)

+24 contact .012 VD -33.71 (-33.75)

+24 contact .013 VD -34.88 (-35.00)

+24 contact .014 VD -36.14 (-36.25)

+25 contact .012 VD -35.71 (-35.75)

+25 contact .013 VD -37.04 (-37.00)

+25 contact .014 VD -38.46 (-38.50)

JC 04 Aug 2017, 14:56

Maxim: If I understood correctly you do wear glasses with a real prescription when not doing GOC? May I ask what your actual prescription is? If so then if you get GOC glasses with the same frame I don't think you have to worry about your family catching you. My own glasses are -4 and I regularly wear -9 and nobody can tell the difference -- even my wife who knows that I switch between the two. I even showed up with +5 glasses in front of her and she never saw a difference, which gave me confidence to wear them in front of other people with whom an explanation would be more complicated then with her. Outside of our community and eye care professionals people just don't pay attention to such things. I also would be very surprised if anyone other then an ECP noticed contacts under glasses.

Maxim 04 Aug 2017, 13:01

A small amendment: I regularely doing both, hyperop and myop simulation, with +6.00 or - 5.00 glasses.

Just three days ago, I did a 300 miles car ride plus customer talks with the -5.00 glasses and + 5.00 CLs on the eyes (this is the deviation, the exact values are based on my actual prescription.

One remark only: I feel, that the contact lenses on the eyes are much easier to detect with plus glasses, as they have a substantial magnifying effect. With the +6.00 glasses, this effect might be an estimated 150 percent.

With glasses for myopia, this is the opposite effect, the eyes are an estimated 60 percent in size with -5.00 glasses.

If somebody would ask me, why I am wearing glasses PLUS contact lenses, I would just say, that the lenses are soaked with an antibiotic medication, this is my idea at least.

My experience is, that walking and driving seems to be easier with the minus glasses (-5.00), and more difficult with the plus glasses. Until now, I have been driving the car without problems with the minus glasses, but I never used the plus glasses for driving (with one exception many, many years ago from London to Manchester, with +7.00 then). The plus glasses I have been using in town, in the subway or for many, many hours in long distance trains. I always forgot after minutes only, that I am wearing glasses, it's quite natural for me, and I have to be careful not to return to my family home still wearing those "odd" -5.00 or + 6.00 glasses - nobody at home knows about my 'obsession'.

I had started GoC when I was studying business, especially international business. As a student, I wrote to companies in Hongkong for CL samples and glasses samples, pretending I would act on behalf of European companies interested in business with these objects. Sometimes I bought glasses with lenses, complete for less than a Dollar per pair, when our companies had already trade relations with them and sold for 50 or 100 Dollars. Even Zenni is not really cheap, as Chinese exporters sell nowadays as cheap as 20 cent per standard lens.

NJ 04 Aug 2017, 10:05

Sallust, the others gave you good advice. I will only add a couple of thoughts. First, if you have no particular preference for plus or minus glasses, go with the minus glasses because, for a given prescription strength, they are easier to wear. This is especially true for high prescriptions, where strong plus lenses limit your vision in ways, mostly peripheral vision, that no amount of practice will reduce. Minus lenses don't really do this.

I'm not sure that all the 'experts' here (none of us a really experts) have experience in GOC, but the prevailing wisdom seems to be to start with weaker scripts and work up. While that might be easier in some ways, it's also expensive. My experience, for what it's worth, was to start with +20 glasses right out of the gate. It took several weeks to get used to them, but I did. The high minus glasses I tried took much less time for me to get used to. YMMV

Cactus Jack 04 Aug 2017, 07:59

Thanks JC,

You have been paying attention and the information you provided Sallust is excellent.


We can help you, but I have a couple of questions and suggestions.

1 Where do you live? I need the country because it affects my suggestions.

2. What is your occupation. GOC suggestions are affected by your visual environment.

.Initial suggestions.

1. You need an eye exam. If you have a refractive error, I suspect it will be small. Your actual complete prescription is the starting place for GOC.

2. Before getting an eye exam, you need to do two things:

A. Read "how to Study for an Eye Exam". I think you can find it here or on the Vision and Spex site. IF you cannot, I will re-post it here.

B. Do the simple home refraction test. That will give us an idea of your approximate sphere refractive error, but it cannot provide any real estimate of any Astigmatism.

If you do the above, that will help determine the symptoms or complaints to mention to the Examiner the you go for the exam. Once we know your actual refractive error (is any) we can suggest what to do about finding out two very important things, what Base Curve (BC) and the Diameter (DIA) you need in contact lenses. Soft Contact Lenses are pretty forgiving, but if they are too tight or too loose, they will be uncomfortable to wear and potentially damaging to the Cornea.

Please be aware that GOC is NOT and inexpensive endeavor, but once you get past the initial stuff listed above, the expenses are not ridiculous, unless you do it wrong. Whatever you do, DO NOT buy existing glasses with the idea of finding contact lenses to make them wearable. That rarely works because of the possible difference between your Cylinder and Axis (if any) and Cylinder and Axis in the glasses.


JC 04 Aug 2017, 06:53


Here are my personal experiences at different correction levels. Your experience will be somewhat different then mine for a few reasons. First I am 37 and you are 19, which means I will have less accommodation available and hyperopia will have more of a bite. Secondly I am naturally nearsighted around -4. As Cactus Jack puts it this means my brain already has been programmed to see with minus glasses and I don't notice effects you might. My brain is not programmed to see with plus glasses meaning what I see is likely exaggerated.

+5 glasses: When first pitting in the contacts everything is very blurred, but within maybe 20 seconds or so my distance vision adapts fairly well. Without glasses in typical indoor lighting I can see distances okay, but it takes a noticeable concentration and effort. Reading is mostly not possible unless the text is large. In bright outside lighting after a while I can almost forget my distance vision is impaired. Reading might be possible with great effort, squinting, and probably a headache. With glasses everything is clear of course, and much bigger then what I am used to. I have to be careful on steps because they are actually smaller then they appear to me. The apparent motion when I move my head is not what I am used to and this sometimes causes a little motion sickness.

-4 glasses: I can not see distance objects clearly nor making out any writing more then a foot or so from me unless it is very large. I can easily identify blurred objects and most people wouldn't know I am hindered unless I had to read or identify a person from a distance. I can not read a book or phone from a "normal" reading distance, but I don't have to bring them so close as to be noticed by most people. If I were to try to read a computer screen I would be leaning in close enough that anyone around me would know something is up. With glasses I can not really give you a good idea of what it is like as this has always been my normal reality.

-9 glasses: Everything is very blurred regardless of distance. I can recognize most large objects by color and shape but smaller objects (like glasses for example) might be hard to locate unless I am quite close to them. In bright daylight I can walk around and navigate well, but at dusk or nighttime I feel helpless. To read anything I will hold it so close to my eyes, possibly closing one of them, that anyone around would immediately know I have a serious vision problem. With glasses again I can not give you a great description as this is normal for me, other then to say everything will be a little smaller and it may be harder to make out small text at a large distance due to the size rather then the blurriness.

JC 04 Aug 2017, 06:11


Some of resident experts here, notably Cactus Jack, will be able to help you out with calculations, power suggestions, etc. The first step will be to get a contact lens fitting.

As far as your decision between minus and plus glasses goes, that of course is up to you by my suggestion would be plus contacts and minus glasses. You said with plus glasses you would limit yourself to around +5. Since you are 19 you should still have substantial natural accommodation, which means when you wear minus contacts without glasses to simulate hyperopia your eyes will neutralize a great deal of the power themselves. Yes when you first put them on your vision will be blurred, reading will be difficult if possible at all, and you might get eye strain and headaches. But all in all you will likely be able to adapt and see okay. If you go the other route and choose plus contacts to simulate myopia then without glasses there will be nothing you can do to see better other then get close to objects or wear glasses.

Our experts will also warn you about starting with too high a prescription. Since you have never needed corrected lenses going from nothing to strong glasses could be too much in one step. Listen to what they say, they are experienced and have helped many of our members achieve what they have been looking for.

Best of luck.

Sallust 04 Aug 2017, 03:55

I've contemplated GOC many times but never actually indulged beyond wearing some drug store readers briefly. I'm 19 so there is a bit of an error margin to work with, luckily. I had my eyes examined last several years ago and I had 20/20 or near 20/20. Even if I could have gotten glasses they would've been a miserably paltry -.5D or so, ones wich I would be ashamed to wear.

So I've got a blank slate. I've been lurking around for qiite a while and am familiar with the realities and limitations.

Here are some of my questions:

1. I am not sure which would be more satisfying, plus lenses or minus lenses. I appreciate both, but plus starts heavily distorting around 5/6D and minus takes until upwards of 10D before the specs begin to look strong IMO. (I'm leaning towards plus specs, minus lenses, unless there is an issue with that.)

2. I don't know the calculations, so a couple pointers and tips would be nice.

3. more about how it looks to be hyperopic without with and without correction, and if it is at all possible to get a amblyopic effect simply through two different Rxs.

4. I've been a glasses admirer for years, but never a wearer, so just general thoughts on how to choose an Rx that is satisfying both in the mirror and behind the lenses.


Davey 01 Aug 2017, 00:59

Thanks Cactus Jack.

Cactus Jack 31 Jul 2017, 21:58


I believe your GOC combination has more MINUS than is required and you are Over Corrected. You did not mention your age, but I suspect you are compensating for the excess MINUS, by using your Ciliary Muscles and Crystalline Lenses to add some PLUS internally.

There is an interconnection between your Focus Control System and your Eye Position Control System that causes your eyes to converge when you try to focus close. The systems do no know if the additional PLUS is for focusing close or you are compensating for over correction, and your eyes try to converge or cross and you see double.

I will help you with the calculations, but I need your age, occupation, and your COMPLETE actual prescription.

It is subject to revision, but a "back of an envelope" calculation indicates that you have about -2.25 diopters too much MINUS in your GOC combination. If you are young enough, you should be able to deal with the extra -2.25. The double vision might go away if you can learn to not respond to the over correction, perhaps with some exercises. Or, you can get prism (probably Base Out) in your glasses. You might be able to find out how much prism you need by doing the Simple Prism Test described on the Vision and Spec' website.


Lurking 31 Jul 2017, 20:15

Given the current topic, I figured this would be good time and thread to share my recent and very first time with GOC with high plus glasses.

My real rx is -4.00, the contacts are -20.00 and my glasses are +12.00. VERY exciting from my perspective, with only 2 minor problems that I hope improve with time. First, I think I may have gotten contacts that are a diopter or so too strong because seeing close objects can be a real challenge.

The other issue a bit more annoying. With my contacts in and glasses on I can see quite clearly as long as I keep one eye closed or else I see double. One of my eyes even crosses. Will this go away after some time.

Cactus Jack 31 Jul 2017, 08:29


I think you should start with less than +18, but here are the suggested numbers.

Your current prescription:

R Sph -0.50 Cyl -0.25 Ax 130 Add 2.50

L Sph -0.50 Cyl -0.50 Ax 25. Add. 2.50

Desired Glasses Sphere: +18.00

Estimated Vertex Distance; 12 mm

18.00^2 = 324 /1000 = 0.324 x 12 = 3.89

Vertex Distance effects of PLUS glasses are increased at the Cornea. Therefore, the effective power of the Glasses at the Cornea are:

+18.00 + 3.89 = +21.89

Your current Sphere “eye power” is +0.50 (reverse of the -0.50) for a total of +22.39.

Theoretically, you will need -22.39 contacts. However, there are two complicating factors.

One: You probably can’t get contacts in 0.25 increments. You might be able to get either -22.00 or -22.50, but I suspect it will not be easy or inexpensive.

Two: At 57 you have very little accommodation. That means that you cannot internally add any compensating PLUS. That means that the GOC combination needs to be pretty close or maybe a little on the PLUS side (IOW the -22.00 contacts. Less MINUS is more PLUS). Because the VD effects are significant, you may be able to compensate by adjusting the glasses slightly.

Please remember also that GOC at high prescriptions is a very inexact science and there are no guarantees, ever.

Your GOC glasses prescription with the -22.00 contacts needs to be:

R Sph +18.00 Cyl -0.25 Ax 130 Add 2.50

L Sph +18.00 Cyl -0.50 Ax 25. Add. 2.50

I suggest, in addition to site down when you try the combination, that you take some motion sickness pills a half hour before trying them. At alternative is having a container handy in case you have motion sickness because of the radical difference between what your eyes perceive and what your semi-circular organs sense.


Neville 31 Jul 2017, 05:34


You'll love the interchange from high minus to high plus GOC. High plus are difficult but the challenge will give you the desired buzz. Tip, sit down for a while after putting on high plus glasses and orientate yourself.

Daey 31 Jul 2017, 01:21

My Rx

R spy -0.50 Cyl -0.25 Ax 130 Add 2.50

L Sph -0.50 Cyl -0.50 Ax 25. Add. 2.50

Davey 30 Jul 2017, 13:33

I,m 57 years young I live in the U.K. I,m thinking of +18.00 glasses as I think this the max strength I can get at a reasonable price off the inter web., I would love to meet up with other GOCers, could we perhaps have aGOC wearers badge"

Davey 30 Jul 2017, 13:29

Hi Cactus Jack, I don't have my prescription to hand until tomorrow but I did use the old calculator years ago to get into -27.50 glasses with +20.00 contact lenses which I wore straight away with no problems, as the years have passed the glasses are probably -1.00 diopter too strong as I move them down my nose a little bit for distance.

Cactus Jack 30 Jul 2017, 11:57


It is an Excel file, I have misplaced the link, but many people have stopped using it in preference to doing the calculations by hand. GOC is not a very exact science, particularly when there are significant changes between the actual prescription and a GOC combo. High prescriptions are very touchy because of very significant Vertex Distance effects. Doing the calculations by hand helps you get acquainted with the underlying optical principles.

We will be happy to help you with the calculations, but we need to start with your Actual complete prescription, your age, where you live, and your target glasses prescription.

Vision occurs in the brain, your eyes are merely biological cameras. Significant changes in prescription usually means that your brain has to learn how to process the new images. With rare exceptions, most people with a natural high prescription have learned how to process the images delivered to the visual cortex gradually, over a period of years. For that reason, it is best to start GOC with a small change and work up to your target glasses prescription.

That does not mean that you cannot start with a big change, but if not done carefully, it can be a hazardous experience, particularly going to a significant PLUS prescription. Loss of peripheral vision can mean missed curbs and stair steps. Also, there can be significant changes in apparent speed of motion when you move your head, which causes motion sickness.

Please let us help make your GOC adventures, pleasant ones.


Davey 30 Jul 2017, 09:51

Hi all, does anybody remember a calculator somewhere on here that calculates the contact lenses you need for GOC when you input your prescription and your glasses strength, I fancy having a change to strong plus lenses instead of my minus lenses, thanks.

Chino 27 Jul 2017, 08:00

This message is for David. I sure hope that you're still reading these. When you had your IOLs implanted, did the doctor also perform a peripheral iridotomy/iridectomy? If so, have you had any issues/problems from that? Any visual disturbances or artifacts as a result of that procedure?

I had read of someone else who had an iridotomy and was experiencing some annoying effects from that. I just want to be absolutely sure that I want to go through with this. I'm probably going to take the leap in the next 7 or 8 years.

Many thanks,


Cactus Jack 26 Jul 2017, 14:16


She is used to wearing Low Plus glasses and wearing -7.75 glasses is a change of nearly -10 diopters. That is a much larger change than wi typically suggest. Her brain has to learn how to deal with the smaller images on her Retinas.

It is possible that the GOC powers need to be adjusted. Unfortunately, VD effects with _7.75 glasses are only 0.06 diopters per mm, which means that moving her glasses closer or further away from her eyes do not have much effect, but it does have some.

Can she move the glasses closer to or further away from her eyes and detect any difference in her distance vision? Which works best?


Mask 25 Jul 2017, 00:46

Hi she has had lenses for 10 years

The problem she has is that it's hard to walk with goc

She finds it difficult with distance

When she walks

She has no problems o drive a car or watch tv mm

Sparky 24 Jul 2017, 21:00

Hi cactus jack .the new prescription I posted is correct .no cylinder this time.

Cactus Jack 24 Jul 2017, 17:09


The numbers seem pretty close to what I calculate.

Can you describe what she is experiencing with the GOC combination. She could be experiencing problems with the contact lenses. Typical problems are dry eyes, poor fit, and / or low oxygen transmission.

Has she worn contact lenses before?


Mask 24 Jul 2017, 13:50

Hi would like some help with lenses and glasses for my girlfriend

she has

L +2,00 cyl -0,75


add + 1.50

H +1.50

add + 1.50

Goc +8.50 lenses



Cylinder -0.75

Axel 100

ADD +1.50


ADD + 1.50

But she does not think it works well

What should I change?

Cactus Jack 24 Jul 2017, 10:10


The Right Eye Sphere is very close to my calculations, but I think the Left Eye needs to have a bit more MINUS, -9.50 or even -9.75. You did not indicate any Cylinder in the recent prescription, but the -0.25 of cylinder in the glasses you ordered should not cause much problem. Is the new subscription you posted, your complete prescription?


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