Normalized under full prescription

I was talking to a friend about how I choose normalized, and the question came up how much under full prescription it was. It never occurred to me before to think about it that way when I reduce. I just observe what my eyes are seeing and consider whether the stimulus they get is ideal.

I’m guessing this difference varies greatly from person to person based on so many factors (daily routine, lighting, environment, etc). But I played around with my test lens kit the other day and estimate that my full prescription is probably around 1 diopter higher than my normalized. It surprised me that they weren’t closer. But I guess my ability to active focus well makes up for a lot.

Has anyone else noticed what their typical normalized difference is to full prescription?

I’m not talking about the difference on your first reductions, where over-prescription can distort these comparisons. But I’m curious to hear from those who are beyond the initial “figuring things out” stage, and have been seeing steady improvement.

I’ll be very interested to hear answers to this well-framed question. I’m guessing that there will be differences of opinion. Among experienced and successful EMers, that may just reflect differences of experience.

The 1D sounds about right to me.
If you have ever edited a photo you surely know that it is not a single value but a range in sharpness / contrast that all look OK. You’ll go for the sharper image if the details are all important (to be examined close-up) and a softer one if you want people to see the whole picture (landscape at a distance - as too much sharpness would make the photo difficult to take in all at one glance).
My opto measures my eyesight and then lets me choose from 3 options depending on how sharp I want to see at distance as it is a personal preference. All are full corrections! The 3 options are around 20/20, 20/15 and 20/13 which is about a range of 0.5D. I used to choose 20/15 that meant that I could read 20/20 any time and 20/15 most of the time, giving me 20/13 on a sunny holiday…
With EM we are anyway aiming for not more than 20/20 correction and then drop 0.25D from it. A 0.25D drop typically gives me an average 20/30 challenge which equals to -0.5D.
So adding the 0.5D challenge of the normalised and the 0.5D range of “correction to overcorrection” it sounds good. And then I haven’t even mentioned AF…
Question is: when you measure that eagle eye correction with the test lenses, would you be comfortable to wear them all the time or if worn at home e.g. in the kitchen while preparing food or for smart phone’s screen you’d get dizzy and tired. That you could get used to eventually, of course, but at the price of your full prescription increasing…


When you say full prescription are you talking about the prescription that the opto gave you?
If so, optos will still “over-prescribe” every time you go in unless you specifically tell them otherwise.

I opened a can of worms when I went to the opthomologist and Jimmy showed me that they were measuring my eyes at a Visual Acuity of 1.2 rather than 1.0. For EMers we would regard this as leading to an overprescribed reading while optos just think they’re doing you a favour and giving you super acuity.

This reading of VA 1.2 contributed at least a whole diopter difference to my personal measurements.

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I’m thinking of not over-prescribed. Basically, what gives a person the equivalent of normal vision without lenses. Usually considered 20/20 without lenses.

I realize that is not very precise. But estimates are better than nothing when trying to see what people are experiencing. I keep wondering if there is any sort of consistent pattern, or at least a range that is typical.