Need Guidance as I am confused with the Prescription

At first eye doctor:
Eye test result:

-5.75(SPH) and -0.50(CYL) in both eyes
(measurement with lenses)

At second eye doctor:
Eye test result:
-6.00(SPH) and -0.25(CYL) in right
-5.75(SPH) and -0.25(CYL).in left
(measurement with device and lenses)

I know Normalized and Differential depends person to person. But what should be my ideal Normalized and Differential be? Should I decrease my cylinders?
My screen hours are around 6-8 hrs daily.

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The only problem that you really have is deciding which of the two prescriptions to use as the starting point. As they are very close, it doesn’t matter all that much. You can use the standard guidelines for working out your differentials, which should be the first step, and waiting before you reduce your normalised.

You also do not say what you are wearing right now, or if you know what the prescription of those glasses are. If they are slightly lower than the prescriptions you mention above, they may be fine to use as normalised for the time being.

Welcome to the forum, and good luck.


That is a fairly big reduction for normalised, but it depends on how far you can read on the Snellen chart with those. I assume you have a Snellen chart, preferably a 6m one, but 3m will do as well. If you don’t have one, you can find one to print out on the website or you can buy a commercial one. If you can read the 20/40 line with your current glasses you should be fine, unless you do a lot of driving in difficult conditions, which might be dangerous. If you feel you see well enough to be safe for now, I would suggest you get your diffs first, based on your usual distance to screen, and use these for a while before worrying about norms. You may find, as many people do, that using diffs for screen work will reduce your myopia quite fast in the beginning.

I am assuming from your local time that you live in India. If you have a friendly optometrist (more common in some parts of the world), you could use their eye chart to check on your distance vision with your current glasses, and ask them if they can help you find the right correction (no more than absolutely necessary) for your usual screen distance. You could call these your computer glasses, as they will not understand the term differential. With your low cylinder, it is very likely that you can do without cylinder correction in your diffs, so ask them to leave it out when measuring for computer glasses…

As you have medium high myopia, you will be on the EM journey for a while, and you should learn to measure your own eyesight and keep records of your progress, if you have not already done so. Alas, this means doing a fair bit of reading on the website and the forum. But it will be worth the effort in the end.


Got it, First I will get the differential.


Get good at measuring and soon you will know all you need.

Sub-scriptions instead of pre-scriptions. :wink:

Somehow better to use something more accurate than their terminology, which presumes medical device, medical condition, something wrong with you, dependent on their approval, all those things.

We’re subscribers to their lens treatments.


Yes, I am practicing and keeping the logs.

yeah for sure

If I understand correctly these ~-5.75D eye test results are recent and you didn’t start wearing these glasses yet, but you were wearing -5.00D SPH with -0.50 CYL in both eyes for 2 years until now.

Does it mean that the pair of glasses with -5.00D and -0.50CYL was enough for driving and in the evenings or in indoor environment? If so, I’d say that pair can be your normalised and you can just enjoy getting clearer and clearer distance vision with them until it is time to drop from them.

The -0.25 or -0.50 CYL is almost negligible, but because you already wore glasses with cyl corrections for at least 2 years, your brain might have got used to having the added cyl correction.
I’d suggest the first differentials - used with your work screen - should be equal (your original glasses and one of the test results suggest equal eyes, don’t start introducing complexity with non-equal SPH correction) and with no or max 0.25D cyl (as statistics shows less cyl is relatively easy to tolerate close-up).
For the SPH value in your differentials you will need to find out for yourself how much to reduce depending on your screen distance and set up. Maybe a pair of reading glasses put in front of your normal glasses can help you determine the ideal strength for differentials.

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Yeah, those results are recent and I think I am wearing CYL numbers since 7-8 years.

Yes before these 2 months but now the clarity is less thats why I took the eye test then I was shocked by seeing this much increment in SPH numbers so I took it again and results were more shocking then previous one.

For differentials: After the 7 Day E-mails the first thing was desperately finding the less SPH spectacles so I got a -4.50 SPH(for temporary use). I have a appointment with optometrist and check my differential.

By opto measurement your eyes seem to have deteriorated by 0.75D. But don’t forget that optos always prescribe glasses to give clear vision at night driving - so the overpresciption is just coded. In real life you use your glasses in more optimal situation - more lights.
Most probably your eyes have gotten worse a bit, but only by 0.25D or 0.25D and that is why your -5.00D with -0.50cyl will be perfect for your first norms.
Just a tip: if you mention your differentials to the opto, call them computer glasses and tell him/her that you have good lights around your desk area and you felt that the full description was too much to wear. Apparently optos like this explanation better :stuck_out_tongue_winking_eye:


:smiley: Sure, I will do that.

Better off, if you’re old enough, say you’re looking for reading glasses. Asking for computer glasses will get you around +0.75 diopters of adjustment (or 1/2 to 2/3 of your +ADD measurement based on age) depending on the optometrist. However, if you ask for readers, you’ll end up with somewhere between +1.00 and +2.00 diopters of adjustment depending on age. That will get you a heck of a lot closer to the +1.50 ± 0.25 diopter offset that most people are going to want for their differentials. :slight_smile:

That said, unless you think your opto is open-minded enough to go along with it, don’t mention anything about EM. Just ask for your full prescription and use that to baseline your adjustment for differentials. Then 4-6 weeks later, you can measure at home to figure out your normalized offset. Though ultimately, if your optometrist doesn’t go along you can always find a new one.